More Liquid Cooling Diagrams [Archive]

MacUnit

Jun 17, 2004, 05:34 PM

Appleinsider publishes (http://www.appleinsider.com/article.php?id=508) more diagrams of the Liquid Cooling System found in the high end PowerMac G5s.

The new cooling system is apparently necessary for higher density PowerPC 970FX chips according to the Apple senior director of desktop product marketing (http://www.internetnews.com/ent-news/article.php/3366061):

From AI (at the end, first link above):
>>
In a recently published self-training course on the new line of Power Mac G5 computers, Apple confirms that all models feature IBM's 970FX PowerPC G5 processor.

"Power Mac G5 (June 2004) models use the PowerPC 970FX processor. Previous Power Mac G5 models used the PowerPC 970. Compared to the 970, the 970FX has a smaller die, higher speeds, and has been optimized more for higher performance."

The dual 2.5 GHz Power Mac G5 model, which is the only model to utilize the liquid cooling system, will begin shipping from Apple in July.
<<

I don't get it...

...if the new cooling system is necessary for higher density PPC 970FX chips...:eek:

...and *all* the new PMac models (including the 1.8 and 2.0 dualies) have 970FX chips (not vanilla 970 chips as before)...:D

...then something ain't right :confused: [i.e. Why does only the 2.5 dualie need the new liquid cooling and not the others? ] :rolleyes:

If they are all 90nm 970FX chips (running at different speeds) and only the 2.5 needs the liquid cooling system, then can we conclude that the cooling problems are more related to processor speed (GHz) and less related to manufacturing processes (90nm vs. 130nm)? :o

Or do some of these news/rumor sources have the facts confused? :(

---MacUnit

DGFan

Jun 17, 2004, 05:40 PM

...and *all* the new PMac models (including the 1.8 and 2.0 dualies) have 970FX chips (not vanilla 970 chips as before)...:D

...then something ain't right :confused: [i.e. Why does only the 2.5 dualie need the new liquid cooling and not the others? ] :rolleyes:

If they are all 90nm 970FX chips (running at different speeds) and only the 2.5 needs the liquid cooling system, then can we conclude that the cooling problems are more related to processor speed (GHz) and less related to manufacturing processes (90nm vs. 130nm)? :o

Or do some of these news/rumor sources have the facts confused? :(

---MacUnit

Cooling is related to processor speed and surface area. Obviously only the 2.5 reaches the threshold where the old heatsinks can't handle the load.

Something from the barefeats article that caught my eye was the comment that the new dual 2.0 is identified as 7,3. I would assume the dual 2.5 is also. Which makes one wonder what 8,1 is....???

iriejedi

Jun 17, 2004, 05:41 PM

So we see the drawings... we know the seekrit... why the 6 week+ delay for shipping? Let's start a predict the actual shipping date pool. :rolleyes:
Um I say Aug 2nd... the original ship date until SJ realized that Aug 2nd IS NOT July. No more bad PR for Steevie!

I'm so excited...my first new mac in 5 years - a record as once I went 23 months... that sucked!

IJ

Jeff Harrell

Jun 17, 2004, 05:44 PM

How do you benchmark Logic Pro and Final Cut Pro on an Intel proc?

By comparing them to Cubase and Avid Media Composer.

legion

Jun 17, 2004, 06:06 PM

"power density"

:D :D :D :D

...obviously a marketing guy

legion

Jun 17, 2004, 06:13 PM

By comparing them to Cubase and Avid Media Composer.

Problem is anyone who's actually used all of those programs know that there is no direct way to compare them. For instance, for CubaseSX2 vs LogicPro, what constitutes the reverbs or the track count, what audio equipment is being used in conjunction, etc. For video, what makes up "supporting" the number of video layers.. real-time rendering, just playback, etc. Plus, why would you compare to Avid MC and not AvidXpressPro (which supports 12 realtime layers out of the box) or Avid Adrenaline (which supports alot more.) Either way, real professionals are not swayed by marketing numbers. They'd have a specialist sales rep show them the machines and actually use them in comparison. These silly numbers are for general laymen to say "machine x" is more powerful than "machine y", but it doesn't mean anything to actual users who make real money off of the product.

Sun Baked

Jun 17, 2004, 06:17 PM

From the pic's it looks like a pump for the top of the chips and heatpipes for the bottoms.Seems like I keep repeating myself. ;)

The LCS is for the CPU only, replaces the previous monster sized stack of plates on the 2.0GHz and below machines.

The heatpipe is for the Voltage Regulators on the daughtercard, it was also there (and still is) on the 2.0GHz and below machines.

legion

Jun 17, 2004, 06:20 PM

BTW, Cubase SX2 and Avid MC and Avid XpressPro and Avid Adrenaline are all available for MacOS X. Why not at least attempt to look fair and use the same programs?!! They are all used professionaly on both platforms.

(maybe, Apple is trying to push another agenda too?? or maybe they specifically tweaked their in-house programs to make the results possible...)

fatbarstard

Jun 17, 2004, 06:22 PM

And this is reason people that we won't see a 5 in a Powerbook for some time yet... these chips are little furnaces!!! You just can't grab them and shove them into a confined space like a PB without causing serious damage to your legs or desk or whatever....

Still - a water cooled chip is a cool thing to have on your desk... maybe you could reverse engeineer it somehow and turn it into an aircon unit?? Would that suck or blow?? :D

MacUnit

Jun 17, 2004, 06:28 PM

Cooling is related to processor speed and surface area. Obviously only the 2.5 reaches the threshold where the old heatsinks can't handle the load.

Right, so the surface area of the 970FX (90nm) chips are all the same. Check. And this surface area is smaller than the 970 chips used before (130nm) in the older PMacs. Check.

That leaves ONLY processor speed (clock rate) as the differentiator (for heat generation and therefore cooling system requirements) on the 970FX machines (1.8D, 2.0D, 2.5D). Yeah, I expect the faster chips to produce more heat that the slower chips.

But the dude from Apple said (and this is where I have problem): that it is the higher density PowerPC 970FX chips that make it necessary to use the liquid cooling. Well...if all the new dualies have the 970FX chips (i.e. the density is the same because the chip design is the same -- same masks, etc), then why only liquid cooling for the top end? Speed (i.e. clock rate), not "chip density" (i.e. process shrink to 90nm) is "apparently" the source of the heat problem.

Was the Apple dude just talking jive marketspeak, or was he misquoted or paraphrased incorrectly? (I can't find the original quote from the links above).

Any chipheads with knowledge out there?

---MacUnit

The Red Wolf

Jun 17, 2004, 06:29 PM

The Dual G5 systems requiring a liquid cooling system need it to keep the machine quiet. No one wants G5s that sounds like G4 MDD. Unless you're in to sticking your head down the front end of a turbo jet engine. The Towers are "industrial" machines. Power over portability. I don't think anyone is planning on dual 2.5s in a 12" PowerBook. But one could imagine much like a 3.5 inch drive was made smaller for a laptop... An LCS or other interesting form of cooling in a compact and efficient set up for a single 2.5. Like encasing the board in a thermal diffusing hydro-polymer. Science fiction sure. But Apple is capable of innovation. There is a difference between what goes into an industrial cheese grater and one used on one of those cooking shows. Same idea, cheese grating, but size and application come into play. G5 Towers are an enigma of Industrial Power and carry a certain elegance. But the LCS within them I doubt will be used in what we see here today for smaller machines built around the G5.

Sun Baked

Jun 17, 2004, 06:35 PM

But the dude from Apple said (and this is where I have problem): that it is the higher density PowerPC 970FX chips that make it necessary to use the liquid cooling. Well...if all the new dualies have the 970FX chips (i.e. the density is the same because the chip design is the same -- same masks, etc), then why only liquid cooling for the top end? Speed (i.e. clock rate), not "chip density" (i.e. process shrink to 90nm) is "apparently" the source of the heat problem.The 2.5GHz chip DOES operate at a higher energy density than the 2.0GHz PPC 970 or 970FX.

The 2.5GHz PPC970FX operates at a maximum power dissipation between 100-110W -- the 2.0GHz PPC970FX (50-55W) and below chips operate at much lower maximum power dissipation numbers.

Somebody did a quick calculation based on the surface area, and it does operate much higher than the other chips.

tazznb

Jun 17, 2004, 06:35 PM

Cooling is related to processor speed and surface area. Obviously only the 2.5 reaches the threshold where the old heatsinks can't handle the load.

Something from the barefeats article that caught my eye was the comment that the new dual 2.0 is identified as 7,3. I would assume the dual 2.5 is also. Which makes one wonder what 8,1 is....???

X-Station 3.0 Ghz :eek:

stcanard

Jun 17, 2004, 06:36 PM

Is this diagram thing getting old or is just me??

Maybe not just you but people with your interests...

Until they actually ship I can't get enough diagrams to see how it's working. A no-maintenance, (relatively) low cost water cooled consumer system. Definitely worth looking at as many design specs as possible.

But then again I've used a soldering iron on a 6 month old laptop motherboard ... the inside of all my electronics is just too much to stay away from.

ethernet76

Jun 17, 2004, 06:58 PM

By comparing them to Cubase and Avid Media Composer.
Cuebase runs on a mac too, quite wonderfully. My powerbook 1.25 ghz kicked the crap out of my friends overclocked athlon.

Why wouldn't they just use Cuebase for both, as cuebase has more features, and will probably be slower on a PC and a mac.

Apple benchmarks are shady.

eSnow

Jun 17, 2004, 07:06 PM

But the dude from Apple said (and this is where I have problem): that it is the higher density PowerPC 970FX chips that make it necessary to use the liquid cooling. Well...if all the new dualies have the 970FX chips (i.e. the density is the same because the chip design is the same -- same masks, etc), then why only liquid cooling for the top end? Speed (i.e. clock rate), not "chip density" (i.e. process shrink to 90nm) is "apparently" the source of the heat problem.

Well, the point is that the old 970 were not able to reach 2.5Ghz - the higher density allows for the speed increase - which brings a higher power dissipation. Furthermore the smaller structural size leads to the same amount of transistors on a smaller surface area, thereby exacerbating the problem.

So, the Apple guy was right in that the structure shrink is part of the problem - the other part is the higher speed you pointed out.

shawnce

Jun 17, 2004, 07:08 PM

The 2.5GHz chip DOES operate at a higher energy density than the 2.0GHz PPC 970 or 970FX.

The 2.5GHz PPC970FX operates at a maximum power dissipation between 100-110W -- the 2.0GHz PPC970FX (50-55W) and below chips operate at much lower maximum power dissipation numbers.

Somebody did a quick calculation based on the surface area, and it does operate much higher than the other chips.

Can you show documents that talk about the 2.5GHz version burn over 100W of power.

I doubt it to be true if the 2.0GHz 970FX is only burning 55W (which I found a document online a while back stating). If the cores are the same, the process is the same, then the power dissipation should roughly scale linearly with clock speed. In other words I would expect the 2.5GHz version to be burning roughly 70W.

ethernet76

Jun 17, 2004, 07:20 PM

Right, so the surface area of the 970FX (90nm) chips are all the same. Check. And this surface area is smaller than the 970 chips used before (130nm) in the older PMacs. Check.

That leaves ONLY processor speed (clock rate) as the differentiator (for heat generation and therefore cooling system requirements) on the 970FX machines (1.8D, 2.0D, 2.5D). Yeah, I expect the faster chips to produce more heat that the slower chips.

But the dude from Apple said (and this is where I have problem): that it is the higher density PowerPC 970FX chips that make it necessary to use the liquid cooling. Well...if all the new dualies have the 970FX chips (i.e. the density is the same because the chip design is the same -- same masks, etc), then why only liquid cooling for the top end? Speed (i.e. clock rate), not "chip density" (i.e. process shrink to 90nm) is "apparently" the source of the heat problem.

Was the Apple dude just talking jive marketspeak, or was he misquoted or paraphrased incorrectly? (I can't find the original quote from the links above).

Any chipheads with knowledge out there?

---MacUnit

Ok. Here is how it works, as I use to overclock my P3 to ridicous speeds and saw heat increase significantly.

When you increase the clock cycle, you increase the amount of energy flowing through the chip and more and more of the energy escapes as heat. This is some sort of non-linear equation deal.

Theoretically, if you ran the processor slow enough, you wouldn't need a heatsync. For example, when I halved my P3 600 down to a 300 I could turn off the processor fans and see temperatures of about 100 degrees F. Compare this to a Pention 2 at 300 and you might of overheated because the P3 design was a lot more efficient than the P2.

Now compare this when I got the 600 to run at 933. To keep it at safe running temperatures I had the side panel door open and a 14-inch industrial fan blowing inside the case. It still ran at about 170 degrees F.

While the 970FX is more efficient than the original 970, it isn't a huge improvement.

Now considering the following. Take 1000 people put them in a 130 by 130 foot room. Then, take the same 1000 people and put them in a 90 by 90 room. Which room is going to be hotter?

So in effect, the chip generates more heat because the high clock speed in a smaller space. The chip has an effective surface area of 8100 nm squared. The original has twice that surface area.

So in reality liquid cooling was going to happen at some point. Apple has the unique ability to start the move into the off-the-shelve computer liquid cooling because they build the computers and set the pace for the mac world. Intel however is at the mercy of what Dell puts in there, and has hindered pentium 4 clock increases. Along with the pentium 4 being a ****ty chip.

ethernet76

Jun 17, 2004, 07:25 PM

Can you show documents that talk about the 2.5GHz version burn over 100W of power.

I doubt it to be true if the 2.0GHz 970FX is only burning 55W (which I found a document online a while back stating). If the cores are the same, the process is the same, then the power dissipation should roughly scale linearly with clock speed. In other words I would expect the 2.5GHz version to be burning roughly 70W.

The 970FX at 2 ghz consumes far less energy.

Typical power 51W@1.8GHz<- 970
25W@2.0GHz<- 970fx

Source: http://www.ibm.com/chips/techlib/techlib.nsf/techdocs/7874C7DA8607C0B287256BF3006FBE54/$file/PPC_QRG_2-22-04.pdf

BrianKonarsMac

Jun 17, 2004, 07:27 PM

It's not just you.

It's only water cooling, nothing to get too over excited about.

is it water though? i personally dont think it is. they seem to make a point aboud calling it liquid cooled, not water cooled. no proof obviously, unless u want to crack it open and do a taste test for me :D

g4cubed

Jun 17, 2004, 07:28 PM

This is supposed to fit into a PowerBook eventually? Wow, good luck...

Yea, that radiator hanging off the back would make them a bit heavy :D

Is this diagram thing getting old or is just me??

It's not just you.

It's only water cooling, nothing to get too over excited about.

And to those less interested or bored with the subject, just don't read those threads. It's your choice.

BrianKonarsMac

Jun 17, 2004, 07:30 PM

Well, the point is that the old 970 were not able to reach 2.5Ghz - the higher density allows for the speed increase - which brings a higher power dissipation. Furthermore the smaller structural size leads to the same amount of transistors on a smaller surface area, thereby exacerbating the problem.

So, the Apple guy was right in that the structure shrink is part of the problem - the other part is the higher speed you pointed out. tje reason the density is such a problem is because you can longer cool the heat with a fan, its so hot in such a small area the air would never cool the center of the chip, just the edges. a liquid cooled device is able to pull heat off the entire chip.
And to those less interested or bored with the subject, just don't read those threads. It's your choice.
but that would require far more common sense than they have...the simplicity of this idea boggles the mind :p

g4cubed

Jun 17, 2004, 07:33 PM

is it water though? i personally dont think it is. they seem to make a point aboud calling it liquid cooled, not water cooled. no proof obviously, unless u want to crack it open and do a taste test for me :D

It is a combination of water and propylene glycol, a clear liquid used in automobile antifreeze.

Sun Baked

Jun 17, 2004, 07:35 PM

The 970FX at 2 ghz consumes far less energy.

Typical power 51W@1.8GHz<- 970
25W@2.0GHz<- 970fx

Source: http://www.ibm.com/chips/techlib/techlib.nsf/techdocs/7874C7DA8607C0B287256BF3006FBE54/$file/PPC_QRG_2-22-04.pdfWe were talking Maximum Power Dissipation which is the actual design criteria -- not the typical number.

And the Maximum number is about twice the Typical.

And here is an IBM Presentation on Power Dissipation (http://forums.macrumors.com/showthread.php?t=73147)

---

>shawnce

Ask this guy where he got the number for this post (http://forums.macrumors.com/showpost.php?p=888159&postcount=77)

Though it probably isn't too far off (or even a conservative number) -- it's the leakage that's killing us at 90nm.

g4cubed

Jun 17, 2004, 07:35 PM

but that would require far more common sense than they have...the simplicity of this idea boggles the mind :p

Something a lot of people seem to be lacking... :D

alexf

Jun 17, 2004, 07:53 PM

I was wondering whether these liquid-cooled machines will actually be quieter than the other models...

Also, is a newly-released Rev. B any noisier / quieter than a similarily configured Rev. A?

g4cubed

Jun 17, 2004, 07:57 PM

I was wondering whether these liquid-cooled machines will actually be quieter than the other models...

Also, is a newly-released Rev. B any noisier / quieter than a similarily configured Rev. A?

I'm not sure about the Rev.
But generally the water cooled are alot quieter because of less fans

Chryx

Jun 17, 2004, 08:03 PM

But the dude from Apple said (and this is where I have problem): that it is the higher density PowerPC 970FX chips that make it necessary to use the liquid cooling. Well...if all the new dualies have the 970FX chips (i.e. the density is the same because the chip design is the same -- same masks, etc), then why only liquid cooling for the top end? Speed (i.e. clock rate), not "chip density" (i.e. process shrink to 90nm) is "apparently" the source of the heat problem.

Was the Apple dude just talking jive marketspeak, or was he misquoted or paraphrased incorrectly? (I can't find the original quote from the links above).

Any chipheads with knowledge out there?
---MacUnit

yeah, the surface area is all the same, but the higher clocked one is going to put out more heat, perhaps quite a lot more than the 25% clockspeed rise indicates (someone at IBM claimed 50w typical for the 2.5 which is DOUBLE the 2.0Ghz 970FX)

So you have the same surface area, and twice the heat, you need to more aggressively get that away from the die, hence the watercooling.

dongmin

Jun 17, 2004, 08:12 PM

tje reason the density is such a problem is because you can longer cool the heat with a fan, its so hot in such a small area the air would never cool the center of the chip, just the edges. a liquid cooled device is able to pull heat off the entire chip.

but that would require far more common sense than they have...the simplicity of this idea boggles the mind :pWell, not exactly, Mr. Common Sense.

The air does not directly "cool the center of the chip" in the Rev-A machines ,as you imply. It never has. Both use a system to move the heat from a small concentrated area (the chip) to a larger surface area (heat sink, radiator) which is then cooled by moving air over it via a fan. It's basically the same principle, except in the liquid cooling system, a mechanical pump actively moves the material around. I supposed it's more efficient than just using conduction via metal.

Abstract

Jun 17, 2004, 08:19 PM

Okay from a non-computer guy point of view, I can understand how MacUnit is confused, and I think I can explain it to him. If the "wires" (ie: die size)are smaller than before, and the amount of power that must flow through the chip is the same as before, then the amount of power flowing through every length of the wire (ie: every metre, cm, nm, whatever) at any given time has increased. This is what's causing the increase of heat.

My problem with even my own explanation (as well as theirs) is that I thought that the smaller the process became, the less heat that would be generated from these chips. If the first gen 2.0GHz chips didn't need liquid cooling at 130nm, then I expected that by going to 90nm would make a 2.5GHz much easier to do. I would understand if they found it difficult to make a 2.5GHz cpu using the 130nm process, but since they shrank the die size, it should have been quite easy to ramp the speed up a bit, right?

jsw

Jun 17, 2004, 09:33 PM

Yea, that radiator hanging off the back would make them a bit heavy :D

On a related note, anyone know how much weight the LCS adds? Apple's site says the G5s weigh 44.4 lb (http://www.apple.com/powermac/specs.html) but then goes on to qualify that with "Weight varies by configuration and manufacturing process."

Interesting that they're so exact (to the tenth of a pound). An average? The lowest weight?

Anyway, my Rev A dual-2 G5 weighs so much already that I am afraid to add anything else inside of it for fear that it will collapse into a miniature black hole. I wonder how much additional weight the LCS adds.

Not a real problem. Just a curiosity. And perhaps an issue for those of you who will have to carry one with its built-in flesh-cleaving flat handles.

jared_kipe

Jun 17, 2004, 09:37 PM

Here is the thing that should satify most of your thoughts. The 90 nM chips do make less heat. Thats the point of the reduction of process size. However, they are also smaller, and thus harder to take heat away from. So while they do make less heat, it is hard to cool them. There is where the enigma is.

As for a G5 in a laptop, as stated before me, just because it has a large heatsink doesn't mean it won't work in a laptop. First of all, I don't know if you all have looked at the heatsinks on any of the late G4 towers, but they were very large. What makes them fit in laptops is #1 you don't use dual processors, #2 you have them clocked down a bit (in the begining), and #3 you use the select processors that will reach a desired speed at lower voltage than the desktop CPU. I used to over clock pentiums for people who needed new hardware but couldn't afford it. Every computer overclocks different, and the main thing that raised heat for me when I overclocked was increased voltage not MHz.

g4cubed

Jun 17, 2004, 09:49 PM

Every computer overclocks different, and the main thing that raised heat for me when I overclocked was increased voltage not MHz.

I don't know anything about the P4s or over clocking for that fact, but I was lead to believe increasing the voltage, increased the MHz :confused: Maybe just a misconception on my part, but agree about increase voltage increase heat.

jakemikey

Jun 17, 2004, 09:49 PM

Not a real problem. Just a curiosity. And perhaps an issue for those of you who will have to carry one with its built-in flesh-cleaving flat handles.

No kidding. I call my G5 "old ironsides". Those handles have to be the most ergonomically incorrect handles ever...and they KILL when you have to move it even a moderate distance.

Bigheadache

Jun 17, 2004, 09:57 PM

I don't know anything about the P4s or over clocking for that fact, but I was lead to believe increasing the voltage, increased the MHz :confused:

Thats not true. Sometimes you need to increase voltage to get your overclock stable, but its not always the case.

On my Athlon XP, I overclocked from 1.8Ghz to 2.2Ghz without increasing core voltage, but some others have had to tweak the core by 0.05v. Generally the more MHz you try to overclock, the more likely you will need more core voltage, but as with all overclocks, each case can be different. What jared said is correct.

shawnce

Jun 17, 2004, 11:19 PM

>shawnce

Ask this guy where he got the number for this post (http://forums.macrumors.com/showpost.php?p=888159&postcount=77)

Though it probably isn't too far off (or even a conservative number) -- it's the leakage that's killing us at 90nm.

Well it looks like he is guessing at this number...

... (maximum wattage of 102 - I'm assuming this figure from the typical)
... Let's say that the 970fx at 2.5ghz is the same as the 130nm part at 2.0ghz

It would be great to see some real documentation in regards to the 970 and 970FX parts. To bad IBM doesn't appear to put in any out at the moment.

However IBM does have a little quick reference guide that states the following...

Typical power 970:51W@1.8GHz 970FX:12.3W@1.4GHz, 24.5W@2.0GHz

So if you take the typical and double it as a bench mark for maximum you get the 970FX at 2GHz is burning about 49W. Then note that the 2GHz is 43% faster (clock wise) then 1.4GHz and the power difference is about 100% or 2x then... you can guess that the 970FX running at 2.5GHz would be burning around 74W maximum (1.5x the 2GHz part).

Anyway I am surprised that if the cores are the same that the active power dissipation isn't scaling linearly (the static dissipation should be similar for the same core at the same core voltage). I wonder if a core voltage difference exists between the 970FX running at 1.4GHz and the one running at 2.0GHz. If so that would explain it.. ah yes the 1.4GHz part runs at a core voltage of 1V while the 2GHz part runs with a voltage of 1.3V.

So factoring that the active component will vary linearly with clock rate but to square of the voltage we are looking at a delta of about 70% caused by the voltage.

Anyway that easily negates my 2x multiplier in the above so the 970FX running at 2.5GHz likely runs more closely to 25% more then the 2.0GHz (assuming the same core voltage) or in other words more like 62W.

... but who knows without some better numbers on the 970FX.

aafuss1

Jun 17, 2004, 11:22 PM

According to 'The Inquirer' some of the AppleInsider images of the cooling system had to be removed :
http://theinquirer.net/?article=16646

But these images can still be viewed:
http://images.appleinsider.com/images/g5lcs2.gif
http://images.appleinsider.com/images/g5lcs1.gif

Maxx Power

Jun 17, 2004, 11:25 PM

The apple marketing guy is a bozo. He obviously is good at marketing though, which is probably why apple hired him. Challenged power density ? That's just a fancy way of saying -> "I work in marketing, and i have no idea what i'm talking about except what the guys above me tells me to say and think, and i dress in bright bright pink".

Power Density Increased, because per interconnect size decreased. The total number of transistors remain roughly the same (no change of processor implementation). That means the area of the die got smaller, which means per unit area heat dissipation increased if clock speed is increased from previous generation. Density may have been increased, but the total is what matters, you see your desk lamp ? It's so hot and bright because the effective heat dissipation per unit area is high, so you probably wouldn't want to touch a 60 watt bulb in operation. In contrast, your bathtub water heated to a comfortable temperature lets out more than 60 watts of heat but hardly hot to the touch.

Bottom line is, the only reason they used water cooling is obviously because the new G5's are dishing out too much entropy compared to previous generations. I don't know what kind of a clown would believe the PR marketing firm of ANY company.

LethalWolfe

Jun 17, 2004, 11:25 PM

Problem is anyone who's actually used all of those programs know that there is no direct way to compare them. For instance, for CubaseSX2 vs LogicPro, what constitutes the reverbs or the track count, what audio equipment is being used in conjunction, etc. For video, what makes up "supporting" the number of video layers.. real-time rendering, just playback, etc. Plus, why would you compare to Avid MC and not AvidXpressPro (which supports 12 realtime layers out of the box) or Avid Adrenaline (which supports alot more.) Either way, real professionals are not swayed by marketing numbers. They'd have a specialist sales rep show them the machines and actually use them in comparison. These silly numbers are for general laymen to say "machine x" is more powerful than "machine y", but it doesn't mean anything to actual users who make real money off of the product.

AvidXpressPro can do 1 stream of uncompressed SD video in real time. Please provide a link that says it can pull 12 streams of DV in RT. FCP 4.5 + a dual 2.5 G5 can pull more SD streams in RT than an Avid Adrenaline running dual 2.8 Xeons. Not to mention it costs a hell of a lot less.

Is this an end-all, be-all stat? Or even a very important one? No, but it's a good eye catcher and that's why it's there.

And of course you are going to pit Apple hardware + software against "PC" hardware and software. This is marketing the Apple platform against the PC platform.

"Real pros" don't base decissions off of sales reps demos. They talk to other pros, request demo units to play with on their own, and look for info in the trades. Going by the word of a sales rep is worse than going by what you see on the company's website.

Lethal

Sun Baked

Jun 17, 2004, 11:51 PM

Well it looks like he is guessing at this number...

... (maximum wattage of 102 - I'm assuming this figure from the typical)
... Let's say that the 970fx at 2.5ghz is the same as the 130nm part at 2.0ghz

It would be great to see some real documentation in regards to the 970 and 970FX parts. To bad IBM doesn't appear to put in any out at the moment.Not quite double, but it's close enough for estimates until somebody can extract the real numbers from IBM.

Searching around, there was a thread here about this article putting the 970FX at 50W for a 2.5GHz unit...

http://www.infoworld.com/article/04/02/16/hnpowerdown_1.html

Phinius

Jun 18, 2004, 12:11 AM

The 2.5GHz PPC970FX operates at a maximum power dissipation between 100-110W -- the 2.0GHz PPC970FX (50-55W) and below chips operate at much lower maximum power dissipation numbers.

The Pentium 4 Prescott at 3.4GHz uses a maximum of 127 watts. With the 970FX potentially achieving another 20% boost in frequency to 3GHz, it could have a higher maximum power use than a 3.4GHz Prescott P4 if your calculations are right.

dongmin

Jun 18, 2004, 12:24 AM

Something from the barefeats article that caught my eye was the comment that the new dual 2.0 is identified as 7,3. I would assume the dual 2.5 is also. Which makes one wonder what 8,1 is....???There's been at least 3 threads on this topic. The consensus is that the 8,1 is a brand-spanking new iMac with totally new architecture (meaning G5 or e600). Please see

http://forums.macrumors.com/showthread.php?s=&threadid=73831

legion

Jun 18, 2004, 01:32 AM

AvidXpressPro can do 1 stream of uncompressed SD video in real time. Please provide a link that says it can pull 12 streams of DV in RT. FCP 4.5 + a dual 2.5 G5 can pull more SD streams in RT than an Avid Adrenaline running dual 2.8 Xeons. Not to mention it costs a hell of a lot less.

Is this an end-all, be-all stat? Or even a very important one? No, but it's a good eye catcher and that's why it's there.

And of course you are going to pit Apple hardware + software against "PC" hardware and software. This is marketing the Apple platform against the PC platform.

"Real pros" don't base decissions off of sales reps demos. They talk to other pros, request demo units to play with on their own, and look for info in the trades. Going by the word of a sales rep is worse than going by what you see on the company's website.

Lethal

A) I never said 12 streams in uncompressed.. but it can do 12 streams 5:1 (DV25).

B) I also said that real pros don't go by marketing, but use the software and hardware. No one takes the word of anyone when you can get demo machines to work with (if you have the budget) I never said that anyone would go "of sales reps." I said that real pros demo the software provided by a sales rep.

Also, lets not get confused as to what FCP is capable of at film quality. I think you and I know who uses FCP and who uses Avid when it comes to big budgets and finishing and onlining video.

The basic question, though, is why Apple didn't do comparisons using the same software as the ones they chose run on both platforms (Cubase SX2 and Avid) Would it be that they know they wouldn't have anything to tout???

Peej

Jun 18, 2004, 01:53 AM

tje reason the density is such a problem is because you can longer cool the heat with a fan, its so hot in such a small area the air would never cool the center of the chip, just the edges. a liquid cooled device is able to pull heat off the entire chip.

but that would require far more common sense than they have...the simplicity of this idea boggles the mind :p

It's not a cooling area problem (middle vs sides), it's that the chip can be cooled more efficiently with a liquid than with air. Liquid (water plus additives to preserve it and raise the boiling point) is more dense than air, and can therefore be a much more efficient conductor of heat, in this case it takes it away from the source. Being a liquid, it can flow over the heat source and then into an area where it can be cooled by a fan, then recirculated to the heat-producing area again. Try this experiment: Put a can of warm soda in the freezer, make sure it's not touching anything, and put another can in a bucket of ice water. Wait 15 minutes. See which one is colder. Hey, that's it. G5 powerbooks will come with water-proof cases and aluminum ice buckets. Yes!

peej

savar

Jun 18, 2004, 02:00 AM

jbrown

Jun 18, 2004, 03:06 AM

.....top up with anti-freeze in November:)

Are these the same chips in the xServes?? If so why no liquid cooling in them?

Also, what is the liquid? I thought I read water - which is an active compound I believe.

What if it leaks? Say 5 years down the line.

displaced

Jun 18, 2004, 04:40 AM

I thought that when the chips shrank, the power consumption shrank also. So that 2.0 ghz on a 110 process consumers more power than 2.0 ghz at 90. Is this not true? Or does the increased density more than offset this savings?

Thinking back to my days when I had time to care about overclocking and all that stuff... :)

A die shrink means smaller chip features & interconnects. That means you need less voltage to make the chip work. This is good, because as you raise the clock speed you begin to get electrical interference within the core. Lowering the voltage means less interference, and thus higher clock speeds.

Lowering the voltage also means it's less power hungry and, nominally, a cooler CPU. But, by the time you've cranked the clockspeed up (which you now can because of the voltage reduction) you're still spitting out a lot of heat. Plus, the smaller die size (surface area) means it's harder to get rid of that heat.

AidenShaw

Jun 18, 2004, 07:44 AM

What if it leaks? Say 5 years down the line.

Apparently, Apple's anticipated this already:

http://www.apple-x.net/modules.php?op=modload&name=News&file=article&sid=962&mode=thread&order=0&thold=0&POSTNUKESID=03dfab6176dccb4d5f83a36b15819375

Of other interest, "Nitrile or rubber glove should be worn when handling an LCS module that is leaking or suspected to be leaking.

Evidence of leaks would include corrosion around fittings in the LCS coolant system, a light green or red liquid present, or a slick or slimy feel when handling the part.

For leaks or spills, wipe up the fluid using rags, paper towels, or other suitable materials. Dispose of all cleaning materials according to local laws and regulations ...

Note that the Apple LCS uses simple spring type hose clamps on the hose connections. In contrast, one of the overclocker's water-cooling kits from http://HighSpeedPC.com uses positive compression fittings instead:
http://www.highspeedpc.com/Merchant2/graphics/00000001/CMS_4.jpg

http://www.highspeedpc.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=HSPC&Product_Code=CMSkit&Category_Code=Kits

eazyway

Jun 18, 2004, 08:28 AM

"power density"

:D :D :D :D

...obviously a marketing guy

Actually makes a lot of sense since we went from a 135 nm chip to a 90 nm chip if the total power output is the same for each chip then the density on the 90 nm is much greater. Power per unit of area. More heat radiating per sq nm. Thus the higher temperature and the cooling problem.

MacUnit

Jun 18, 2004, 09:12 AM

Actually makes a lot of sense since we went from a 135 nm chip to a 90 nm chip if the total power output is the same for each chip then the density on the 90 nm is much greater. Power per unit of area. More heat radiating per sq nm. Thus the higher temperature and the cooling problem.

OK, that makes sense. But that would imply that the new 1.8 and 2.0 machines are going to be LOUDER than the old 1.8 and 2.0 machines because they do not have the enhanced (liquid) cooling but still need to dissapate more heat (per unit area).

Do we all expect the new machines without the LCS to be noisier than the old ones? Will the fans have to be on more at higher speeds?

---MacUnit

shawnce

Jun 18, 2004, 09:45 AM

OK, that makes sense. But that would imply that the new 1.8 and 2.0 machines are going to be LOUDER than the old 1.8 and 2.0 machines because they do not have the enhanced (liquid) cooling but still need to dissapate more heat (per unit area).

Do we all expect the new machines without the LCS to be noisier than the old ones? Will the fans have to be on more at higher speeds?

I don't expect them to be any louder and in fact I expect them to be quieter on average.

Remember they actually dissipate less heat then the prior versions (sure in a smaller area die wise however note the chip package is the same size as the 970, 25mm x 25mm) so overall you have less heat to remove from the system. One can assume that the current passive air cooling used is sufficient to pull heat fast enough from the 1.8 & 2.0 GHz chips and hence they do not need the liquid cooling. If they can pull out the heat fast enough you will likely not need any additional air flow and in fact you may likely need less air flow because the chip dissipates less overall. Again the chip package for the 970 and 970FX is the same size/type and they [IBM] have likely done their best to get the heat to spread rapidly out of the whole of the package as much as possible.

In fact the 2.5 GHz doesn't _need_ the liquid cooling either given that top end P4 have higher power densities then the 970FX at 2.5 GHz and those systems ship without liquid cooling.

I still contend that it is only being used now because Apple expected to have faster chips around this time that would really need to be liquid cooled to be efficient/safe/quiet and they want to start using the system to help bullet proof it for when it very much needed and they had it ready and stocked obviously.

With that said, their is no doubt that using the liquid cooling for the 2.5 GHz will help keep it quiet since it can pull heat out of the chip more efficiently and spread that heat out, evenly and efficiently, to a large cooling surface then a passive cooling system would.

MegaSignal

Jun 18, 2004, 09:56 AM

I'm not sure about the Rev.
But generally the water cooled are alot quieter because of less fans

Because there will still be the other fans for the other sections of the cabinet, as well as fans for the radiators, plus all of the ancilliary motors/pumps/whatever for the LCS, it will probably be a "wash" in terms of overall noise.

I'll bet money on it.

SiliconAddict

Jun 18, 2004, 10:12 AM

We're what? A week and a half away from WWDC and this is the best rumor that can surface at this point!?!?!??! (Note that this isn't a hack on you Arn.)

WEEEEEE!!!! LC diagrams are released! OMG!! OMG!!! This is so much better then your typical rumor!

Where's the video iPod? Where's the rumor about Apple's Tablet? G5-M PowerBooks?

I want rumors dang it!! :p :cool: :confused: :(

Jeff Harrell

Jun 18, 2004, 10:57 AM

Plus, why would you compare to Avid MC and not AvidXpressPro (which supports 12 realtime layers out of the box) or Avid Adrenaline (which supports alot more.)

They did use Adrenaline. I just oversimplified.

These silly numbers are for general laymen to say "machine x" is more powerful than "machine y", but it doesn't mean anything to actual users who make real money off of the product.

What was the point of this post? Just to be derisive?

I have absolutely had it up to here with people who do nothing but whine about benchmarks and performance tests. If you don't like the results, that's fine. But kindly shut up about it. And leave your "I'm better than you because I snort at glossies" attitude at home. I use a Mac specifically to stay away from that kind of elitism.

Try this experiment: Put a can of warm soda in the freezer, make sure it's not touching anything, and put another can in a bucket of ice water. Wait 15 minutes. See which one is colder.

Here's a much more dramatic experiment: free two blocks of ice in the same size. Put one in a 400-degree oven. Put the other in a sink full of slowly running cold water. See which one melts first. The degree to which water is a better conductor of heat than air has to be seen to be believed.

jsw

Jun 18, 2004, 11:28 AM

What was the point of this post? Just to be derisive?

I have absolutely had it up to here with people who do nothing but whine about benchmarks and performance tests. If you don't like the results, that's fine. But kindly shut up about it. And leave your "I'm better than you because I snort at glossies" attitude at home. I use a Mac specifically to stay away from that kind of elitism.

To some extent, I agree with legion in that benchmarks do not reflect reality for most users unless they happen to do exactly what the benchmark tests.

That aside, though, they are a useful tool for more than just "general laymen" in that they give an idea of relative performance/software strength. Yes, if your business depends on application X, then of course you'll want to see that on each platform to decide what makes sense for you. However, even if, from a purely hardware point of view, two systems are equal, it so happens that the benchmarks show one as being consistently slower, then it indicates to me that software development for the "slower" platform isn't as strong, which is useful for me to know.

So, therefore, I think benchmarks are very useful in that (limited) sense.

However, since I'm not a graphics pro, I really don't care how much faster/slower the G5 is compared to an AMD PC. To me, OS X is such a better OS that, unless the hardware starts to fall SERIOUSLY behind, I don't care what the numbers are.

wdlove

Jun 18, 2004, 11:33 AM

DWKlink

Jun 18, 2004, 12:05 PM

dizastor

Jun 18, 2004, 12:05 PM

I've had a liquid cooling system in my pants for years

g4cubed

Jun 18, 2004, 12:10 PM

Because there will still be the other fans for the other sections of the cabinet, as well as fans for the radiators, plus all of the ancilliary motors/pumps/whatever for the LCS, it will probably be a "wash" in terms of overall noise.

I'll bet money on it.

I didn't say all the fan. :rolleyes: But I guess, to some extent you're right. I've seen a couple of water coolers that were whisper quiet and others noisey as hell. I guess we'll have to see which one Apple selects. :D

shawnce

Jun 18, 2004, 12:15 PM

Should there be any concern about the connectors that Apple is using, as mentioned above?

How will heat and humidity affect the cooling system? Wondering if there might be a condensation problem during high humidity. We have Dew Points in the 60's a lot here is Boston. Occasionally the 72 range.

The liquid cooling system used isn't an AC unit (no compressor or evaporator and the cooling fluid doesn't change density/vaporize) so it doesn't have the ability to cool a target location more then the ambient temperature of the fluid. The liquid cooling system is simply about pulling heat away from one location rapidly and efficiently and transferring that to a much much larger surface area, one that is configured to be air cooled efficiently. It isn't about cooling that surface below ambient temperatures like your fridge or AC unit does.

So I doubt you can get into a situation that can result in condensation build up (without changing the environment the system is in rapidly).

AidenShaw

Jun 18, 2004, 12:22 PM

Wow, looking at the picture of that PC pump posted a few replies back makes you really appreciate the engineering of apple products. The apple LCS just looks like its much more rugged and built of much higher quality materials and craftmanship.

The Apple piece looks more elegant, but of course it should - it's a custom designed piece for one particular computer. The PC part is a universal kit, designed for the hobbyist to adapt to his particular case.

As far as quality - I don't know how one can judge the quality of the pumps, seals, soldering and other details from the photos.

It's very bizarre, however, that Apple is using rubber hoses and spring clamps instead of metal tubes and fittings, or compression fittings. It looks like there are 16 clamps in the system, that's a lot of potential leakage points.

At the very least Apple could have used screw-type clamps instead of those spring loaded clamps. But, I guess the extra expense of higher quality clamps would have eroded the profit margins.

Also - where's the expansion tank?. It doesn't look like the Apple unit has any provision for dealing with the expansion of the fluid as it warms up. Does it just let the pressure increase to push against the seals and spring clamps? Maybe all the rubber hoses swell to absorb the pressure.

BTW, here's what the PC kit normally looks like when installed in a system:

http://www.innovatek.de/contentServ/3.0/www.innovatek.de/data/media/751/CMS_3.jpg

Jeff Harrell

Jun 18, 2004, 12:49 PM

The liquid cooling system used isn't an AC unit (no compressor or evaporator and the cooling fluid doesn't change density/vaporize) so it doesn't have the ability to cool a target location more then the ambient temperature of the fluid.

Incredible nitpick: the limiting factor is the temperature of the air circulating through the heat exchanger. The processors get hot, which makes the coolant hot, which circulates through the heat exchanger. Air moves over the heat exchanger and carries the excess heat of the coolant away.

So it's impossible for a system like this one to get any cooler than the temperature of the air at any point.

I'm sure that's what you meant, Shawn, but I hadn't posted anything in a while. :)

Also - where's the expansion tank?. It doesn't look like the Apple unit has any provision for dealing with...

Why is it so hard for some folks to accept that the people who designed the Apple system do it for a living, and that they've, you know, probably thought of stuff?

usarioclave

Jun 18, 2004, 01:18 PM

It's very bizarre, however, that Apple is using rubber hoses and spring clamps instead of metal tubes and fittings, or compression fittings. It looks like there are 16 clamps in the system, that's a lot of potential leakage points.

At the very least Apple could have used screw-type clamps instead of those spring loaded clamps. But, I guess the extra expense of higher quality clamps would have eroded the profit margins.

Apple's done some goofy stuff before. Back in the powerbook 500 days, you could stick two batteries in them. Apple drained the left battery, then the right battery, but if they drained both at the same time they would have gotten more (ie: longer) performance.

They have weird oversights like that. You'd think that Apple would be as good all the way through, but just like every other company they can't pay attention to everything all the time.

steveh

Jun 18, 2004, 02:39 PM

From the pic's it looks like a pump for the top of the chips and heatpipes for the bottoms.

Looks to me as though the heatpipes are cooling some support chip to one side of the CPU.

AidenShaw

Jun 18, 2004, 02:40 PM

Why is it so hard for some folks to accept that the people who designed the Apple system do it for a living, and that they've, you know, probably thought of stuff?

And when they don't think of it, there are product recalls and revisions. (Wind-tunnel G4s, iBook mobos, PM G5 power supplies, PB power bricks, PB hinges, Ipod mini plugs, ...)

Why is it so hard for other folks to accept that Apple makes mistakes, just like everyone else?

In spite of Apple's vaunted engineering elegance, the G5 LCS has 8 rubber hoses and 16 spring clamps to seal them.

The overclocker's PC cooling system has 3 tubes and 6 positive compression fittings.

I'd certainly prefer to have 6 potential leak points sealed with compression fittings, than to have 16 leak points with spring clamps....

jsw

Jun 18, 2004, 03:00 PM

Looks to me as though the heatpipes are cooling some support chip to one side of the CPU.

See here (http://forums.macrumors.com/showthread.php?p=891808#post891808), among other places.

jsw

Jun 18, 2004, 03:07 PM

In spite of Apple's vaunted engineering elegance, the G5 LCS has 8 rubber hoses and 16 spring clamps to seal them.

The overclocker's PC cooling system has 3 tubes and 6 positive compression fittings.....

And two very long plastic tubes, which I'd suspect would fail at least as often as the short hoses on the G5.

Sun Baked

Jun 18, 2004, 03:08 PM

See here (http://forums.macrumors.com/showthread.php?p=891808#post891808), among other places.I'll repost for the visually challenged...Originally posted by Sun Baked:
The daughtercard looks similar to the old one.

Though they do have the new liquid cooling, so just take a look back at the old pics to see where the remaining heatpipe went...

Remember these old Momentum pics?

G5 Daughtercard View 1 - Bottom (http://www.970eval.com/g5-disassembly/P1010062.jpg)

G5 Daughtercard View 2 - Side (http://www.970eval.com/g5-disassembly/P1010063.jpg)

G5 Daughtercard View 3 - Top (http://www.970eval.com/g5-disassembly/P1010065.jpg) <--- See Left side of board

G5 Daughtercard View 4 - Angle (http://www.970eval.com/g5-disassembly/P1010069.jpg)aka, it's the Power Supply of the daughtercard. ;)

robotrenegade

Jun 18, 2004, 03:27 PM

Can you add these to the first G5's?

jsw

Jun 18, 2004, 03:51 PM

Can you add these to the first G5's?

No need. Wouldn't help anything. And, also, looks like you couldn't anyway without severely messing with the heat sinks.

MikeTheC

Jun 18, 2004, 04:01 PM

At the risk of showing ignorance...

I know that a number of people on here have posted illustrations of comparison between liquid head exchange and air heat exchange, but since the processor isn't (for obvious reasons) bathed in water, I really do not understand how it is any more effective than just blowing air.

I basically agree with the posts here which show concern about potential leaks in the system. I mean, is liquid cooling really worth it? I have seen (online, not in person) several different unique cooling rigs over the years, some of them liquid and others being air. The one I always thought was pretty neat is produced by Shuttle for their XPC system.

To wit:

jsw

Jun 18, 2004, 04:07 PM

At the risk of showing ignorance...

I know that a number of people on here have posted illustrations of comparison between liquid head exchange and air heat exchange, but since the processor isn't (for obvious reasons) bathed in water, I really do not understand how it is any more effective than just blowing air.

...

The liquid cooling systems work better due to the fact that they conduct heat much better than air convects it. Ultimately, of course, they're all air-cooled... but the LC systems get the heat away from the chips more efficiently to the radiator.

Basically, as you say, they don't keep the processor in a liquid, but, in effect, the liquid is used to conduct heat away from the heat sink attached to the chip faster than air alone could.

michaelb

Jun 18, 2004, 04:13 PM

Apple's done some goofy stuff before. Back in the powerbook 500 days, you could stick two batteries in them. Apple drained the left battery, then the right battery, but if they drained both at the same time they would have gotten more (ie: longer) performance.

Goofy is your interpretation. Unless there's some technical effect to draining batteries that only you are aware of, your claim doesn't make sense. If you have one 1500 mAH battery, add another 1500 mAH battery, then you have 3000 mAH worth of power. The computer will still drain this at the same rate.

Now whether you drain that 3000 mAH from one battery at a time, or both batteries together, would give the same operating time. In terms of which is better, by draining one battery at a time, you could replace one drained battery while still working with the other still charged one. That's hardly a mistaken design decision.

AidenShaw

Jun 18, 2004, 04:13 PM

but since the processor isn't (for obvious reasons) bathed in water, I really do not understand how it is any more effective than just blowing air.

In the air cooled system, you have a finned heat sink which is in the airflow. It will be hotter closest to the cpu, and not so hot far away. The challenge is to conduct the heat a long distance from the concentrated heat source, and spread it out without having a hot spot on the CPU. So, you need a thick plate of metal that easily conducts heat (aluminum, copper, silver...) that the fins attach to (or are part of).

With the LCS, the large air fins are replaced by the flowing water. The metal plate (the cold plate) doesn't need to be as big or thick - since the moving water on the other side is so efficient at absorbing the heat. There may be a set of small fins in the water, like here:

http://www.highspeedpc.com/Merchant2/graphics/p-o-mThumb.jpg

See the miniature copper fins inside the water bath?

So, the main advantge to water is that the heat doesn't have to travel far - therefore you can keep the plate cooler.

Other cold plates are at: http://www.highspeedpc.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=HSPC&Category_Code=Blocks

AidenShaw

Jun 18, 2004, 04:32 PM

And two very long plastic tubes, which I'd suspect would fail at least as often as the short hoses on the G5.

Did I say *anything* about the hoses?

Assuming that the Apple hoses are neoprene or some other synthetic, it's unlikely that the lifetime of the poly-vinyl overclocker's tubing would be significantly different from Apple's hose lifetime.

The connections, though, are the worry spots - that's where leaks are more likely.... The PC kit has far fewer connections, and more secure connections (compression vs. spring clamps).

Worry about the clamps, not the hoses.

ffakr

Jun 18, 2004, 05:28 PM

Ok. Here is how it works, as I use to overclock my P3 to ridicous speeds and saw heat increase significantly.

When you increase the clock cycle, you increase the amount of energy flowing through the chip and more and more of the energy escapes as heat. This is some sort of non-linear equation deal.

specifically, wattage is calculated by voltage * amperage. Amperage is often referred to as "current". A cpu that uses 1.5 volts will draw more amperage if you increase the clock frequency or if you actually use it. That's why chips get hotter when they are under load. One way to overclock a processor more is to increase the core voltage. This usually allows you to get a higher clock out of it than you otherwise might. This has the nasty side effect of REALLY driving up the wattage though.. Just think about an increase from 1.5 to 1.8V.. that's +20%. With a chip that would normally be rated at 1.5V and 50 watts.. a move to 1.8v (if all other things remained the same) would mean you are at 60w right away. Then you start increasing the clock....

Theoretically, if you ran the processor slow enough, you wouldn't need a heatsync.
Now compare this when I got the 600 to run at 933. To keep it at safe running temperatures I had the side panel door open and a 14-inch industrial fan blowing inside the case. It still ran at about 170 degrees F.

right, the issue here is, how much current the chip needs to draw at that frequency. You're lucky you got it to run that fast without upping the voltage.

While the 970FX is more efficient than the original 970, it isn't a huge improvement.

Well, there is a decent improvement in the new processor, but IBM is still working out issues with the new processor. The smaller the process (the thinner the gates), the more likely you are to run into current bleed and signal cross talk. You can actually get electrons hopping the traces.. effective screwing everything up. IBM expected a lot of current bleed.. the more current bleed, the more draw the chip will have.. so the hotter it will run. This is a problem with the Intel process.. one of the reasons the Prescotts are HOTTER than the .13 micron Northwoods. IBM actually had a lot of unexpected problems with signal crosstalk, something that caught them off guard.

Now considering the following. Take 1000 people put them in a 130 by 130 foot room. Then, take the same 1000 people and put them in a 90 by 90 room. Which room is going to be hotter?

So in effect, the chip generates more heat because the high clock speed in a smaller space. The chip has an effective surface area of 8100 nm squared. The original has twice that surface area.

this is where your argument has serious issues. The new processors AREN'T 8100 nm^2. That's be REALLY small. They are actually 66 mm^2. The _process_ is .09 micron (90 nm). That's a reference to the size of the features on the die.. not to the size of the processor.
In comparison, I *think* the old 970 was around 100 mm^2. An Athlon64 with 1MB L2 is about 170 mm^2.

Your basic argument is somewhat sound, you just have problems with the details.

The comment from the Apple guy is accurate though. I'm just making up numbers here for an example so bear with me..
say a 2.5GHz 970fx chip runs at 80 watts. That's 80 watts disipated from a 66 mm^2 surface or about 1.2 W/mm^2. An Athlon64 3400+ might also put out 80 watts, but the surface is around 170 mm^2. That's less than 0.5 W/mm^2. Even though both chips are generating the same waste heat, the PPC 970fx is producing 2.5X as much for a given area. That would mean that you need a cooling solution that removed heat 2.5X as efficiently (quickly) with the 970fx as you'd need with the Athlon64. Liquid cooling is more efficient.

Other comment... As for the questions regarding why a 2.5 would be so much hotter than a 2.0.. there could be a lot of reasons.
Firstoff.. it runs faster. More current draw.
Second, it may run at a higher core voltage. it isn't all that uncommon to see CPUs with different rated core voltages even if they are from the same family. The speed bin from the manufacturer is all about stability. If a chip can run stable at a given speed, it's bin'ed at that speed. If they can get some chips to bin a 2.5GHz at a slightly higher core voltage, that's a valid sort. The 1.8 GHz parts may not run stabily at a much higher clock speed even if the core voltage is upped.
We won't know what the core voltages are until IBM lists part specs on the 970fx chips though.

edit: One last point...
back to why liquid cooling is so much better than just air cooling. A lot of people pretty much answered that question by pointing out that the liquids transfer heat quicker than air. I just wanted to add that air is a pretty Poor thermal conductor. The only reason we survive as air cooled creatures is due to the constant evaporation from our skin.. especially when it's really hot. Air is such a bad coolant that it's often used as an excellent insulator. If you look at just about any insulation.. like the fiberglass insulation in most homes or even a down winter coat, it's the dead air between the fibers/feathers that actually insulate. If you put fiberglass insulation in a flat bag and sucked all the air out of it, it'd have a really terrible R value (which, coincidentally is how many times better the insulation is compared to un-trapped air of the same thickness)
So, Air sucks as a coolant.. why does it work so well for things like really hot computer chips and even radiators. It's all about surface area. Computer heatsinks and radiators are designed to provide a vastly greater amount of surface area to the air that is flowing across it. A radiator has even more surface area... there are all those coils of (typically) aluminum that the liquid flows through.. the radiator also has the heat spread out because the coolant flows all through the radiator. Air is still a terrible coolant, but if you flow that fresh air over, say, 100x more surface area than the face of the chip.. and if you do a good job of spreading that energy out over the fins (that is, circulating the coolant to all parts of the heat sink/radiator), it does OK.
In the end, it isn't the liquid that makes the new G5s system so much more efficient, it's the radiator the coolant flows through. If the radiator didn't disperse more heat than a carved slug (heatsink), and if the coolant flow didn't allow better dispersion of that heat (energy),.. the ambient temperature of the coolant would rise too high and the water block wouldn't do anything at all.

Jeff Harrell

Jun 18, 2004, 05:49 PM

Ultimately, of course, they're all air-cooled...

Interestingly, this isn't entirely true. Big computers, really big ones, require chilled facility water and output warm water. So those computers really are entirely water-cooled.

Surreal

Jun 18, 2004, 05:51 PM

Most metals would be bad as tubing

Note that i said most...there are some which have SOME properties which go against what i am about to say, but but the reasons against those are a matter of nuance.)

most metals expand VERY quickly when heated...this would lead to bending if not engineered around (you can compensate..but you are simply giving yourself another factor)

and most metals transfer heat at rate that would make efficient cooling VERY difficult. the tubes would give off heat...

AidenShaw

Jun 18, 2004, 05:55 PM

and most metals transfer heat at rate that would make efficient cooling VERY difficult. the tubes would give off heat...

That's OK though - it's just additional radiator area ;)

The problem, though, would be on the "cold water" side after the radiator. The tubing would pick up case heat on its way to the CPUs.

That would be insignificant, though, mainly due to the original problem that air is not a good heat transfer agent. If it were a problem, the "cold tubes" could be insulated.

jsw

Jun 18, 2004, 05:56 PM

Interestingly, this isn't entirely true. Big computers, really big ones, require chilled facility water and output warm water. So those computers really are entirely water-cooled.

True!

I was referring to just personal computers.

Ultimately, I suppose, they are all cooled by radiation out to space. But that's a few steps beyond this discussion, I think. I suspect we'll at least be at the G7 chip before Apple uses direct-to-space heat sinks.

ffakr

Jun 18, 2004, 06:03 PM

Interestingly, this isn't entirely true. Big computers, really big ones, require chilled facility water and output warm water. So those computers really are entirely water-cooled.

I think even the systems you are thinking of have a closed coolant system though. You probably meant this, but your post reads more like they have it hooked up to the cold faucet at one end and it dumps into a waste pond at the other.

At my last job, the old mainframe had a heat exchanger on the roof. The coolant was run through a heat exchanger that, at one time at least, had liquid nitrogen used in some way.

All liquid coolant systems do recycle coolant in a closed track though as the coolant needs to be treated (or pure water) to prevent mineral buildup. In the end, even a system with an active heat exchanger is ultimately air cooled though. At some point, you need to disperse the waste energy somewhere.. My house isn't simply aircooled, but the freon system dumps heat to the outside heat exchanger which is air cooled.

just picking nits.
ffakr.

pjkelnhofer

Jun 18, 2004, 06:04 PM

True!

I was referring to just personal computers.

Ultimately, I suppose, they are all cooled by radiation out to space. But that's a few steps beyond this discussion, I think. I suspect we'll at least be at the G7 chip before Apple uses direct-to-space heat sinks.
Or maybe that will be how they get the G5 into a PowerBook.

LethalWolfe

Jun 18, 2004, 06:16 PM

A) I never said 12 streams in uncompressed.. but it can do 12 streams 5:1 (DV25).

B) I also said that real pros don't go by marketing, but use the software and hardware. No one takes the word of anyone when you can get demo machines to work with (if you have the budget) I never said that anyone would go "of sales reps." I said that real pros demo the software provided by a sales rep.

Also, lets not get confused as to what FCP is capable of at film quality. I think you and I know who uses FCP and who uses Avid when it comes to big budgets and finishing and onlining video.

The basic question, though, is why Apple didn't do comparisons using the same software as the ones they chose run on both platforms (Cubase SX2 and Avid) Would it be that they know they wouldn't have anything to tout???

A. The original comment was about comparing uncompressed streams on FCP and Avid MC. You brought up the XPro and didn't clarify that you were comparing it's DV streams to the uncompressed streams pulled by FCP and MC. And, if you don't mind, could you post a link showing that the XPro can pull 12 DV streams in RT.

B. My bad, I misread a line in your original post.

"Also, lets not get confused as to what FCP is capable of at film quality"
Just to be a jackass, No one digitally edits a film at "film quality." I could cut a feature using a xfer to MiniDV if I wanted. ;) The Coen brothers seem to have taken to FCP, and Walter Murch, all and all, had a positive experience w/FCP when he cut "Cold Mountain." "Scrubs" has used it since day one and I think they are headed into either season 3 or 4.

I agree, we both know that when it comes to big features, TV shows and commercials it's by-and-large older Macs running Meridien<sp?> based Avids. But FCP is getting more and more looks and replacing more and more Media/Film composers. Right now I think FCP's biggest short coming is largely in media management, and it's just not as refined an editor as Avid. But that's to be expected considering the "age" difference between the two.

Lethal

jsw

Jun 18, 2004, 06:31 PM

Or maybe that will be how they get the G5 into a PowerBook.

"Apple G5 PowerBook - Now Available Exclusively on the International Space Station!"

Might make the $20M for the trip worth it. ;)

shawnce

Jun 19, 2004, 12:09 PM

Incredible nitpick: the limiting factor is the temperature of the air circulating through the heat exchanger. The processors get hot, which makes the coolant hot, which circulates through the heat exchanger. Air moves over the heat exchanger and carries the excess heat of the coolant away.

I see your nit and raise you one :D

Yes that goes without saying however isn't fully accurate depending on what type of cooling system you are talking about (it is correct for the system in the G5).

AC units contain a refrigerant that is compressed into a dense liquid or gas by a compressor. This dense liquid then flows into and out of a heat exchanger to pull out as much heat in the liquid/gas as possible given the ambient temperature of what the heat exchanger is working with (for home AC units often the outside air). The refrigerant then flows to a evaporation coil near the location that you want cooled (the air you want cooled in your house for example). In the evaporation coil refrigerant then under goes a rapid change in density, some times even a phase change, as a result of properties of the refrigerant selected and the device's design. This change in density (increase in volume, etc) requires the up take of energy, heat, from the refrigerants surroundings. This allows the evaporation coil to actually be cooled below the ambient temperature of the refrigerant as it entered into the coil and that can, if cooling air, lower the surrounding air's temperature below the dew point. This is why your cars AC can drip water out of the bottom of it, in fact one feature of AC units is to also remove extra water from the air and it uses the ability to cool below dew point to achieve this (air with less water, lower humidity, interacts less with surfaces and hence feels cooler, etc.).

The point I was making was that the system in the PM G5 doesn't contain a refrigerate like in the above and the cooling system isn't design to utilize/trigger the density/phase change of the refrigerate (at least nothing I see implies that). So the target of the cooling system cannot be cooled below the ambient temperature of coolant or the air used in the heat exchanger used to pull heat from the coolant. So it cannot cool a surface below the dew point of the air around it, so you will not get condensation. Which was the original question asked.

shawnce

Jun 19, 2004, 12:23 PM

At some point, you need to disperse the waste energy somewhere..

You are correct that most often that air is used as the final sink for the waste energy. I just wanted to point out that in some situations water cycled from and back to streams, lakes or the ocean are used as the heat sink. In some situations (in places with abundant water) they actually use water evaporation. Also something that it gaining more traction is the use of the ground itself as a heat sink/source (http://advancedhydronics.com/geoexchange.htm). This style of system can sink a lot of energy. relatively rapidly and efficiently. Building heating/cooling plants are starting to utilize this type of system more and more (at least I have seen more of them being put in place).

Maybe Apple will be the first with a dirt cooled computer :p

wdlove

Jun 19, 2004, 01:11 PM

I see your nit and raise you one :D

Yes that goes without saying however isn't fully accurate depending on what type of cooling system you are talking about (it is correct for the system in the G5).

The point I was making was that the system in the PM G5 doesn't contain a refrigerate like in the above and the cooling system isn't design to utilize/trigger the density/phase change of the refrigerate (at least nothing I see implies that). So the target of the cooling system cannot be cooled below the ambient temperature of coolant or the air used in the heat exchanger used to pull heat from the coolant. So it cannot cool a surface below the dew point of the air around it, so you will not get condensation. Which was the original question asked.

Thank you for the clear and concise explanation shawnce. It improves my confidence since I live in a high humidity area like Boston. The condensation issue could have been quite a problem otherwise.

iris_failsafe

Jun 19, 2004, 07:09 PM

wdlove

Jun 19, 2004, 07:59 PM

Try a multicore power4 chip. It will occupy less area and I bet it can be insulated with aerogel

That aerogel is good stuff. I wish that Lawrence Livermore would be coming with some practical uses. Originally it was for homes. I'm not sure about the use in a G5, why would you want to keep the heat?

jsw

Jun 19, 2004, 09:02 PM

That aerogel is good stuff. I wish that Lawrence Livermore would be coming with some practical uses. Originally it was for homes. I'm not sure about the use in a G5, why would you want to keep the heat?

Excellent point - you certainly would not want to insulate the chip.

Phinius

Jun 19, 2004, 09:19 PM

I'll bet the 2.5GHz 970FX, that is used in the PowerMac, is overclocked and that is the main reason for Apple to use water cooling in the topend model. In other words, IBM is still having production problems with the 90-nm process and that has forced Apple to make a speed improvement for the PowerMac on only one model and to do that the company dramatically raised the heat output by overclocking the 970FX chip to 2.5GHz.

There are several reasons for my conclusion:

1) Apple kept two models of PowerMac at 1.8GHz and 2GHz, while moving the topend up 500MHz. Where are the 2.1GHz-2.4GHz processors? Why in the world would Apple release a 500MHz faster model without updating the speed of the other PowerMacs unless 130nm 970 chips are still being used for the 1.8GHz and 2GHz PowerMacs? Apple might do that as a last resort if there was a shortage of 970FX chips from IBM after several months of production (Apple did turn to overclocking the G4 to 1.42GHz, when they desperately needed faster chips for the PowerMac in order to keep PowerMac sales alive until the G5 arrived). If IBM is able to produce 2.5GHz chips, then there should be 970FX chips available at 2.1GHz-2.4GHz. Afterall, there should be a smaller supply of faster 2.5GHz processors than the slower speeds, since less chips would be able to run reliably at the highest speed.

2) The Xserve is backordered 4-6 weeks. Apple clearly stated in the last quarterly meeting with analysts that the reason for the delay in shipping G5 Xserves was the small supply of 970FX chips from IBM.

3) Apple had to include water cooling after having the G5 PowerMac out only 8 or 9 months and it is only available on a PowerMac that only runs 500MHz more than the slower models? That seems rather odd. It could be that Apple will drop water cooling if IBM is able to produce 3GHz 970FX chips in the next few months. If that is the case, then it would point decisively to overclocking of the 2.5GHz chip.

The upcoming July quarterly sales meeting with analysts should answer whether my hunch is right or not. If the backorder of Xserves was only due to a 970FX chip supply problem from IBM, then it will be rather obvious that there would be a even more severe severe shortage of 970FX chips for the much higher production PowerMacs.

macsrus

Jun 19, 2004, 09:29 PM

In the end, it isn't the liquid that makes the new G5s system so much more efficient, it's the radiator the coolant flows through. If the radiator didn't disperse more heat than a carved slug (heatsink), and if the coolant flow didn't allow better dispersion of that heat (energy),.. the ambient temperature of the coolant would rise too high and the water block wouldn't do anything at all.

Your whole post was right on the money

johnnowak

Jun 19, 2004, 10:42 PM

DWKlink

Jun 20, 2004, 09:27 AM

There are several reasons for my conclusion:

1) Apple kept two models of PowerMac at 1.8GHz and 2GHz, while moving the topend up 500MHz. Where are the 2.1GHz-2.4GHz processors? Why in the world would Apple release a 500MHz faster model without updating the speed of the other PowerMacs unless 130nm 970 chips are still being used for the 1.8GHz and 2GHz PowerMacs?

Isn't this fairly stardard operating procedure for Apple product line updates? Increase the speed/features on the top level machine and just bump the other machines down a level while eliminating the bottom of the line.

nsb3000

Jun 20, 2004, 12:03 PM

This is supposed to fit into a PowerBook eventually? Wow, good luck...

Ya..right. I thought the 970fx were supposed to be cooler... Maybe we will see G5 powerbook in Jan 06? :-(

shawnce

Jun 20, 2004, 01:24 PM

Ya..right. I thought the 970fx were supposed to be cooler... Maybe we will see G5 powerbook in Jan 06? :-(

They do use less power at the same clock speed then a 970. If you use the numbers from IBM almost 50% the power (which is important not only because of heat generation but for battery life if used in a laptop). The change in die size difference however can require more rapid heat transfer then what was done before. In other words the parts product less heat and consumer less energy then before (however the static current is higher so better sleep/nap/etc. management will be needed) but they do so in a smaller area which could require changes in cooling to maintain system design goals.

Also as Apple has stated several times since the introduction of the G5 don't expect G5 laptops any time soon, not sure why some folks let their hopes get ahead of things when statements are made like that... this is Apple who usually doesn't say much of anything about future products, so that should be telling.

Anyway a 970FX G5 running at 1.4 - 1.6 GHz is not that far out of line with the power/heat characteristics of the current top end G4s being used in PowerMacs (ignoring the issues of the faster system buses that would be required).

shawnce

Jun 20, 2004, 01:27 PM

1) Apple kept two models of PowerMac at 1.8GHz and 2GHz, while moving the topend up 500MHz. Where are the 2.1GHz-2.4GHz processors? Why in the world would Apple release a 500MHz faster model without updating the speed of the other PowerMacs unless 130nm 970 chips are still being used for the 1.8GHz and 2GHz PowerMacs? ... If IBM is able to produce 2.5GHz chips, then there should be 970FX chips available at 2.1GHz-2.4GHz. Afterall, there should be a smaller supply of faster 2.5GHz processors than the slower speeds, since less chips would be able to run reliably at the highest speed. Why not look at Apple system updating history? The often up the top end system and bump the prior top end system down to the middle or bottom slot. So introducing a 2.5GHz system and maintaining 2.0GHz and 1.8GHz system isn't a big surprise.

Also would it make sense to have systems in the line up that only differ 4% or 19% clock rate wise? Historically Apple usually has around a 40+% difference between the low end and top end CPU clock speeds for its Power Mac line (look at the Apple hardware docs if you want). The current line up falls at about 38% difference between top end and low end. So I believe this point isn't the most valid interpretation of things.

No doubt IBM had and is having issues delivering parts in the 90nm process (this is not news) and continues to be below expected yields in both volume and clock rates. They also had some issues at the beginning of the 130nm process because the Fish Kill plant was basically just getting up and running back then. It does however sound like they are catching up and getting towards the yields they want.

2) The Xserve is backordered 4-6 weeks. Apple clearly stated in the last quarterly meeting with analysts that the reason for the delay in shipping G5 Xserves was the small supply of 970FX chips from IBM. Actually Apple expects to be caught up with the back orders in the next week or so (they may even be used some of those 2+ GHz 90nm parts to catch up on orders).

3) Apple had to include water cooling after having the G5 PowerMac out only 8 or 9 months and it is only available on a PowerMac that only runs 500MHz more than the slower models? That seems rather odd. It could be that Apple will drop water cooling if IBM is able to produce 3GHz 970FX chips in the next few months. If that is the case, then it would point decisively to overclocking of the 2.5GHz chip. Note 500MHz is 25% more not a bad jump. Apple didn't _have_ to use liquid cooling, they _chose_ to use it because of the design intent for the systems. They want them to be quiet systems and using liquid cooling allows faster more efficient heat transfer. If they didn't use it they would have to pull more air thru existing heat sinks to insure that a great enough temperature delta existed to insure that heat transfer maintained at a sufficient rate to avoid hot spots that exceeded what the die could withstand (they need capacity in the system to deal with peak loads). They decided that they would use a 2.5GHz CPU as the threshold for this (it is also likely that had hoped to have faster CPUs in this time frame, ones that would more likely need liquid cooling to keep the system quiet and within spec, they didn't come up with this cooling is a few months). I doubt that Apple will be dropping liquid cooling when we start to get 3GHz parts, etc. It will only be dropped if Apple decides not to strive for quiet towers or they utilize a different more efficient heat transfer system. The future is about heat management and the used of liquid cooling is a good step towards dealing with the issue as was/is the air flow management in the G5 case.

The upcoming July quarterly sales meeting with analysts should answer whether my hunch is right or not. If the backorder of Xserves was only due to a 970FX chip supply problem from IBM, then it will be rather obvious that there would be a even more severe severe shortage of 970FX chips for the much higher production PowerMacs. Fabrication of chips are done in batch runs with a little downtime between runs for adjustments, refinements and maintenance (more if they have to fix things). If prior runs had issues but those have been resolved they can have little affect on future runs. So they may have stumbled with the first set of 90nm runs that targeted in the ballpark of 2.0GHz chips. If current runs are going well (we will have to wait to see what is said by Apple and IBM) the yields could be good across the range and so no major supply issue may exist. Apple appears confident enough that next month they will have the volumes needed to ship the 2.5GHz systems, a 90nm part (given recent misses I doubt they made this statement without sufficient belief in supply).

Of course without exact tested specs (aka bining) for the CPUs being dropped in the systems some of the parts could very well be "overclocked" (all chips these days are in effect overclocked since active cooling is needed). All this means is that the CPU has to be maintained below a particular temperature threshold (factoring in hot spots) to run at a particular clock speed safely, stably and with sufficient longevity. The liquid cooling system will no doubt give Apple wiggle room to insure that temperatures can be maintained as needed. Supply issues may have pushed Apple to start using the liquid cooling system they had been developing sooner then they original planned but regardless such a system was coming.

The system Apple is using is far from the extreme over-clocking tricks used by some folks which often involves AC units and things like nitrogen baths.

Anyway my general point is that Apple appears to be playing the cards the got dealt and if they are using engineering to help make the best of it good for them. It also shows that have been forward looking enough to have such a cooling system ready (it would take many months to get something like this ready and things tooled to make it).

Phinius

Jun 20, 2004, 01:32 PM

Isn't this fairly stardard operating procedure for Apple product line updates? Increase the speed/features on the top level machine and just bump the other machines down a level while eliminating the bottom of the line.

Apple tends to do that when there is a second round of speed bumps from a given process size. However, with a move to a smaller process size, IBM should have several 970FX speeds from 2.1GHz-2.5GHz. My question is where are those chips except for the 2.5GHz? That and the backorder on the Xserve points towards a continuing production problem with the 970FX. Apple seems to be betting on enough increase in supply for July to at least boost the speed of one PowerMac model by the use of overclocking and water cooling. If it was simply IBM achieving 2.5GHz from higher production, then where are the 2.1GHz-2.4GHz 970FX chips? There should be more 2.1-2.4GHz 970FX processors produced than there are 2.5GHz 970FX chips.

The 970FX seems to be designed as a low cost chip since the L2 cache was not increased as it normally is with a process shrink. The 90nm process size 66mm2 970FX chip is about 70% smaller then the 112mm2 Pentium 4 Prescott and yet it was about the same die size as the P4 on the 130-nm process size. That points towards a likely scenerio of Apple moving the 970FX down to the iMac and perhaps the eMac when the bigger and faster Power5 derived PowerPC 9XX is produced in the next few months.

Phinius

Jun 20, 2004, 02:08 PM

Apple didn't _have_ to use liquid cooling, they _chose_ to use it because of the design intent for the systems.

How do you know that Apple didn't have to use liquid cooling? It's only been about 9 months since the 2GHz 970 PowerMac first came out with a brand new cooling system that has 9 fans.

They want them to be quiet systems and using liquid cooling allows faster more efficient heat transfer. If they didn't use it they would have to pull more air thru existing heat sinks to insure that a great enough temperature delta existed to insure that heat transfer maintained at a sufficient rate to avoid hot spots that exceeded what the die could withstand (they need capacity in the system to deal with peak loads).

What makes you so sure that Apple would have to use the existing 970 heat sinks for air cooling the 970FX? Seems to me that if Apple can come up with a water cooling system then they certainly would have the ability to design more types of heatsinks.

They decided that they would use a 2.5GHz CPU as the threshold for this (it is also likely that had hoped to have faster CPUs in this time frame, ones that would more likely need liquid cooling to keep the system quiet and within spec, they didn't come up with this cooling is a few months).[/quote

It will be at least six months from the time that Apple probably knew about 970FX production problems until the water cooled 2.5GHz PowerMacs are available.

[quote]Of course without exact tested specs (aka bining) for the CPUs being dropped in the systems some of the parts could very well be "overclocked" (all chips these days are in effect overclocked since active cooling is needed).

Name one major PC manufacturer that is using water cooling with either the AMD Opteron or Prescott Pentium 4. I did notice that Sony has a desktop model that uses water cooling, but that seems to be a rare exception.

The 66mm2 970FX is 41% smaller than the 112mm2 Pentium 4 Prescott chip. Since a 3.4GHz Prescott process uses up to a peak of 127 watts, then that means a 2.5GHz 970FX would have to use a maximum of 75 watts to have the same power dissipation per mm2 as the Prescott. 90 watts is about the maximum power use of the 130-nm 2GHz 970 chip. Which means that a 3GHz 970FX would have about the same maximum power use as the 130-nm 2GHz 970 chip. Judging from the average power use figures that IBM has released for the 970 and 970FX, it would seem that the average power use has gone down considerably for the 970FX compared to the 970.

jsw

Jun 20, 2004, 02:17 PM

How do you know that Apple didn't have to use liquid cooling?

As has been mentioned by others, it's likely that the liquid cooling will be truly needed in future G5's, and so Apple has chosen the 2.5 as a trial system which can benefit from the technology, regardless of whether it is literally essential. That gives them some time to work out the problems.

This is just a theory. Maybe the dual 2.5 absolutely required liquid cooling or horrendously load fans. But I suspect that it's a trial run at perfecting an LCS.

And also a cool new thing to get cutting-edge Mac geeks to buy the 2.5 as opposed to the dual-2.0, which is almost as fast in real-world terms.

Makyz

Jun 20, 2004, 02:19 PM

So now Apple is noise obsessed, and we get expensive watercooling nonsense for 500 more mhz.

If its dual processor 2.5 isnt it 1000 more mhz?

I like 1000 mhz more.

Maxx Power

Jun 20, 2004, 02:20 PM

Now considering the following. Take 1000 people put them in a 130 by 130 foot room. Then, take the same 1000 people and put them in a 90 by 90 room. Which room is going to be hotter?.

This is completely misleading and incorrect.

Two basic problems with your analogy

1) by reducing the conductor size and distance of electron travel, you are really looking at a 90 by 90 room with half sized people, or children, if you prefer.

2) At equilibrium, assuming you have the same heatsink for each room that draws a constant amount of heat away, you have the same room temperature for each room. It will take longer for the bigger room to reach equilibrium. This is basic newton's law of cooling, solve the differential equations....

Maxx Power

Jun 20, 2004, 02:25 PM

If its dual processor 2.5 isnt it 1000 more mhz?

I like 1000 mhz more.

Only very very very well coded software that uses two CPU's or threads independently will you see performance increase roughly equals to 90% of 1000Mhz increase.

Dual CPU is capable of running multiple tasks more efficiently, but not as good at running one task more efficiently, for that, a faster single CPU does the trick.

Consequently anyway, for most people, dualies are a waste, more of a marketing thing than actual usefulness.

For servers though, that's another story. The fact that most people don't want to pay 3000+ dollars for a new computer which is once again, just another tool of life, something most people wouldn't get emotionally attached to, is why dualies account for a very very small fraction of the market. The same argument also is true for why apple hardware accounts for a small fraction of the market.

jsw

Jun 20, 2004, 02:34 PM

...Consequently anyway, for most people, dualies are a waste, more of a marketing thing than actual usefulness....

I respectfully disagree. Multi-processor machines seldom do one task much more efficiently (depending on the app, of course), but they almost always do multiple, simultaneous apps more efficiently. A dual-2.5 isn't the same as a single 5GHz one, but it's a lot better than a single 2.5, or even a single 3 (again, aassuming you don't spend most of your time running only one non-parallel app).

Sun Baked

Jun 20, 2004, 02:43 PM

Phinius

Jun 20, 2004, 02:53 PM

Sun Baked

Jun 20, 2004, 03:02 PM

A 3.4GHz Prescott P4 uses an average of 103 watts and the 2.5GHz 970FX uses an average of 50 watts. At 66mm2, the 2.5GHz 970FX typically uses .75 watts per mm2 and a 112mm2 3.4GHz P4 Prescott chip uses .91 watts per mm2. So, the 3.4GHz P4 uses 21% more power per mm2 than the 970FX and yet PC desktop manufactures are able to use air cooling for 3.4GHz Prescott chips and yet Apple turned to water cooling. I still suspect that Apple is overclocking the 970FX to hit 2.5GHz.You are missing the actual design criteria for the 970FX which is the Maximum Power Dissipation (about 100-110W @ 2.5GHz).

Sort of like design the A/C system for a home in Arizona and using the Maximum Summer Temperature instead of the Average Yearly Temp.

If you design for the Maximum, you're living in comfort.

If you design for the average -- you'll be one sweaty human when the temps his 119°F a couple/few days in a row.

Maxx Power

Jun 20, 2004, 03:09 PM

I respectfully disagree. Multi-processor machines seldom do one task much more efficiently (depending on the app, of course), but they almost always do multiple, simultaneous apps more efficiently. A dual-2.5 isn't the same as a single 5GHz one, but it's a lot better than a single 2.5, or even a single 3 (again, aassuming you don't spend most of your time running only one non-parallel app).

I reiterate, for Most People, and by this, go to your local popular computer store, probably WorstBuy or HistoryShop, and inquire what is the fastest selling computer currently, or observe what type of people most frequently comes in and makes a purchase. They barely know the difference between a Pentium and a Computer, what makes spam and e-mail attachment viruses thrive is because your AVERAGE typical computer user is under-literate when it comes to computing. These targets of pepsi commercials and nike shoes are not your power users, they have no need for a multi-gigahurtz processor, much less, a dualie, if downloading pr0n and music is your cup of tea, what i said earlier still stands.

Of course, you are correct when it comes to people who are not the majority, for people who needs to produce things on computers that have multiple threads, a couple of CPU surely beats one. Something i can point out is gaming, on Macs. UT2004 on Macs renders its sound entirely in software, and all done on the CPU. This slows the game to a abysmal 20 fps on a G5 1.6. THis is because there is no hardware accelerated sound for Macs. On a dual 1.8, with the same ATI9600 graphics card, you are looking at doubling in frame rates because the game allocates one of the CPU's to do sound processing and the other for game AI, networking, etc....

PS. Try UT2004 on a PC with hardware 3d sound/EAX, it sounds so much better, even with just two speakers.

Maxx Power

Jun 20, 2004, 03:16 PM

I also agree that DP machines aren't a waste.

If people think dualies are a waste, then they've plain forgotten about OS 9 and it's ability to do ONE thing at a time -- try to do anything else and it crashed or acted like a slug.

OS X handles multiple threads and CPUs more effectively that OS 9 ever did.

Under OS X DP machines are great.

You are correct about the OS 9 situation. I never liked OS 9. Compared to OS 9, i much prefer (don't flame me for saying the truth) windows xp or windows 2000. The windoze series have been able to multi-task efficiently since, i guess, doze 98 ? But many other aspects of that os is pure crap, so let's not get into that.

Regarding dualies, please read my other response a few replies up. To multitask efficiently, you really only need a capable OS, I also regularily use a Doze EKS-PEE machine, and this thing multitasks beautifully on one CPU. I can encode MP4's while watching an episode of this or that, or have some DVD encoded in the background while I listen to music and browse macrumors and share my music online legally (i'm in Canada, it's legal by law) at the same time.

wdlove

Jun 20, 2004, 03:27 PM

Who's to blame for all this? Powermac G4 owners. They whined and bitched constantly about a bit of fan noise. I had a DP G4 PM, and it wasn't that bad. So now Apple is noise obsessed, and we get expensive watercooling nonsense for 500 more MHz.

I want a loud-as-hell 3.5ghz dual G5. Bring it on!

I'm not one of those that complained. Don't think that the noise is a problem at all.

If as some are mentioning the overclocking of the G5 ship, will that shorten its life or cause problems in other ways.

Until Apple says so, I'm not sure which camp is correct. :confused:

shawnce

Jun 20, 2004, 04:23 PM

How do you know that Apple didn't have to use liquid cooling? It's only been about 9 months since the 2GHz 970 PowerMac first came out with a brand new cooling system that has 9 fans. So? They designed and shipped a system which matched their design criteria (their solution was to divide the system into independent zones with independent adjustable rate fans, etc.) and around that same time frame (if not before) they likely already had a liquid cooling system starting to be worked on, to build on this thermal management. They saw the road ahead. In fact the cooling framework setup in the Power Mac G5 chassis and now this liquid cooling is well positioned for the future.

As you state, others don't use liquid cooling... yet they arguably use CPUs with near equivalent and often not greater power dissipation densities then the 970FX (or 970) and with greater over all dissipation per CPU. So if they don't have to use it then Apple didn't have to use either but because of Apple's stronger desire for quiet systems Apple is taking extra steps (just go look at the various silencing products that exists in the market for PC rigs).

What makes you so sure that Apple would have to use the existing 970 heat sinks for air cooling the 970FX? Seems to me that if Apple can come up with a water cooling system then they certainly would have the ability to design more types of heatsinks. This presumes a more efficient heat sink could be designed and fitted then what is already in the PowerMac G5s while still maintaining one of the design goals of a quiet system. It also presumes that such a system, if possible, would be cheaper then using a liquid cooling system (thermoelectric cooling device comes to mind but it still requires more efficient heat sinks to make that work since thermoelectric cooling devices contribute heat themselves as the work). Anyway I fully believe that Apple could have used air cooling for the 2.5GHz, even if they are "overclocked" as you imply, but it likely would have required additional air flow and hence noise (IMHO not much in the case of the 2.5GHz 970FX). Also note that man in the PC overclocking crowd do so without having to use liquid cooling, they often can do it by adding more directed air flow.

It will be at least six months from the time that Apple probably knew about 970FX production problems until the water cooled 2.5GHz PowerMacs are available. 6 months is a rather short time line for the design, testing and tooling of a system like this. I personally doubt this was a reactionary solution as you imply.

Name one major PC manufacturer that is using water cooling with either the AMD Opteron or Prescott Pentium 4. I did notice that Sony has a desktop model that uses water cooling, but that seems to be a rare exception. Name one that is using the divided zone cooling to the extent seen in the PowerMac G5 chassis (yeah rack mount stuff). Also name one that is as consistently concerned about making quiet systems as Apple currently is.

The 66mm2 970FX is 41% smaller than the 112mm2 Pentium 4 Prescott chip. Since a 3.4GHz Prescott process uses up to a peak of 127 watts, then that means a 2.5GHz 970FX would have to use a maximum of 75 watts to have the same power dissipation per mm2 as the Prescott. 90 watts is about the maximum power use of the 130-nm 2GHz 970 chip. Which means that a 3GHz 970FX would have about the same maximum power use as the 130-nm 2GHz 970 chip. Judging from the average power use figures that IBM has released for the 970 and 970FX, it would seem that the average power use has gone down considerably for the 970FX compared to the 970. Well lets look at things this way using numbers from IBM... a 970FX running at 2GHz typically uses 24.5W while a 970 running at 2GHz typically uses 56W (likely a little more but I am doing a linear scaling of values from a 1.8GHz part). Now for max power lets double things, so 49W 970FX at 2Ghz and 112W 970 at 2GHz. The 970FX has a die size of about 66mm^2 and the 970 has a die size of about 118mm^2 (note the chip package is the same size so the heat sink attachment has the same surface area). That yields power densities of 0.74 for the 970FX and 0.95 for the 970 at 2GHz (note the power density for the 970 is 28% more then that of the 970FX at the same clock rate). One factor for the radical power difference is the switch to 1 volt for the core logic, which is thanks to the process shrink as well.

So the existing air cooling system is at least capable of dealing with dissipating 112 W overall while maintaining a rapid enough heat flow to deal with a power density of 0.95 (per CPU). First thing to note swapping in a PPC 970FX for a 970 at the same clock speed in no way requires a change in cooling (why you don't see the liquid cooling across the board and I do believe we will see / are seeing the 970FX across the board in the new systems because they will be cheaper however in the short run they may be using 970 for the 1.8 & 2 GHz versions to clear inventory).

Now what does a 2.5GHz 970FX burn? Well I don't know (no numbers from IBM) but we can likely bound it. The low end can be guessed at by linear scaling of the power dissipation as you vary the clock rate (for CMOS it generally scales linearly with clock rate). So the low end estimate is 62W. Now a high end estimate can be done by assuming that the 2.5GHz 970FX requires the use of 1.3V for its core voltage (the higher core voltage may be needed to insure enough current flow to allow switching at 2.5GHz). That would put the power dissipation at about 105W (for CMOS it generally scales to the square of the voltage). One final guess would be to note the delta in dissipation between the 1.4GHz (12.3 typical) and the 2.0GHz 970FX and assume that delta scales linearly with clock rate. That comes out to 85W and that is just above the average of the other two numbers. I personally believe it is in the 80s.

So the low guess puts the power density at 0.93, the mid at 1.29 and 1.6 for the high estimate (in one of your posts you seem to believe 50 W average which can be guessed to imply about 100W max or a density of 1.51... which is more then the P4 Prescot at 3.4GHz but anyways...). So if the power is at the low end then the existing cooling system is sufficient without additional airflow. If it is towards the mid (I believe it is around the mid) or high estimate then the existing cooling system may not be sufficient (who knows exactly what it tops out at) and hence an alternate system would be needed if one wants to avoid requiring additional air flow (which obviously Apple is trying to avoid). In other words a good enough reason exists to utilize liquid cooling for the 2.5GHz CPU to help keep the system quiet by improving its ability to transfer heat to air (the liquid flowed radiator will be far better at it then a passive heat sink) that one doesn't have to invoke a reasons such are overclocking (however recall my prior wiggle room comment).

Phinius

Jun 20, 2004, 04:23 PM

You are missing the actual design criteria for the 970FX which is the Maximum Power Dissipation (about 100-110W @ 2.5GHz).

Where is there maximum power dissipation figures for the 970FX? You keep stating those numbers but I have yet to find references to them.

Your essentially stating that the maximum power dissipation for the 970FX is 1.51-1.66 per mm2. Compare that to the maximum of 1.13 watts per mm2 for Prescott. Considering that IBM estimates the SPECint score for a 2GHz 970FX is 890 and a P4 hits 884 at 2.26GHz, according to Intel, then the 970FX is working much harder per MM2 than Prescott, while achieving less output. The 970FX achieves 1100 at SPECfp, according to IBM estimates and that compares favorably to a 3.06GHz P4 that has a score of 1077.

IBM SPEC score estimates should improve greatly per MHz for the POWER5 derived PowerPC. IBM has found that the POWER5 is routinely performing 40% faster than POWER4 due to the addition of SMT. It's also likely that this POWER5 derived PowerPC chip will have double the L2 of the 970FX and that should give an additional 10-15% speed improvement per MHz. The downside of the POWER5 compared to the POWER4 is that it has a 25% bigger die size from adding SMT and it also seems to use 25% more watts.

shawnce

Jun 20, 2004, 04:49 PM

Your essentially stating that the maximum power dissipation for the 970FX is 1.51-1.66 per mm2. Compare that to the maximum of 1.13 watts per mm2 for Prescott. Considering that IBM estimates the SPECint score for a 2GHz 970FX is 890 and a P4 hits 884 at 2.26GHz, according to Intel, then the 970FX is working much harder per MM2 than Prescott, while achieving less output. The 970FX achieves 1100 at SPECfp, according to IBM estimates and that compares favorably to a 3.06GHz P4 that has a score of 1077.

I guess IBM should have kept the die size the same while switching to 90nm if folks want to do the math like the above... who cares if they can get almost 4x as many 970FX out of the same wafer then they could before.

If you are talking about a 2.5GHz 970FX you should scale those numbers... so around 1110 SPECint / 1370 SPECfp.

Sun Baked

Jun 20, 2004, 05:01 PM

Where is there maximum power dissipation figures for the 970FX? You keep stating those numbers but I have yet to find references to them.It's a guess, based on some of the numbers that have leaked out -- some a bit above/some below twice the Typical number for other versions of the PPC970.

So basically twice the Typical is a ballpark guess which places you a lot closer to the true Power Usage at 2.5GHz than the Typical number.

The Typical number is closer to what we'd be using if we were using the CPUs in the slewed operation -- and nobody would be happy with 1.3GHz G5's if we stuck at the output of the Typical numbers.

Phinius

Jun 20, 2004, 05:06 PM

At the International Solid State Conference (ISSCC) an IBM spokesperson stated an average of 50 watts power use for the 970FX running at 2.5GHz.

http://www.infoworld.com/article/04/02/16/hnpowerdown_1.html

It was also revealed, in the above link, that the POWER5 using an average 160 watts running at 1.8GHz. Contrast that with the POWER4 using an average of 125 watts. Since the POWER4 derived 970FX and the upcoming POWER5 derived 9XX PowerPC chip are both expected to top out at 3GHz, then the POWER5 derived PowerPC chip will likely use 25-30% more watts per MHz than the 970FX.

At least two people on this forum claim that the maximum power use of the 2.5GHz 970FX is double the 50 watts average power use IBM mentions, or 100-110 watts. In which case bumping the frequency up another 20% to 3GHz should achieve a maximum watt use of roughly 125-132 watts. Moving to the POWER5 core version would move that up another 25-30%, or a maximum of 156-171 watts, if the doubling of average power use is to be believed. Since the average power use of Prescott is 103 watts and the maximum is 23% higher at 127 watts, I tend to believe that the doubling of average power to arrive at the maximum watt usage for the 970FX is probably incorrect. It's more likely that the maximum power use for the 970FX is arrived at by multiplying a figure closer to the 23% average to maximum power use for Prescott.

Phinius

Jun 20, 2004, 05:30 PM

If you are talking about a 2.5GHz 970FX you should scale those numbers... so around 1110 SPECint / 1370 SPECfp.

SPEC has posted P4 3.4GHz, 1MB L2 cache, scores of 1432 for SPECint and 1481 for SPECfp. Which means that for a maximum watt usage of 27% more than the 2.5GHz 970FX, Prescott has a 29% higher SPECint score and a 8% greater SPECfp posting. So again, if a doubling of average watt usage to achieve maximum watt use for the 970FX is to be believed, then the 970 is about as wasteful of watts per output as Prescott. I find that hard to believe since Prescott should be less efficient at a 36% higher frequency than the 970FX, plus the 970FX is made with a silicon-on-insulator coating (SOI), which should cut down on power usage.

Sun Baked

Jun 20, 2004, 05:40 PM

I tend to believe that the doubling of average power to arrive at the maximum watt usage for the 970FX is probably incorrect. It's more likely that the maximum power use for the 970FX is arrived at by multiplying a figure closer to the 23% average to maximum power use for Prescott.Quick, you better call Apple and tell them their engineers are all idiots and deserve to be fired, because you have the correct numbers for the 970FX at 2.0GHz...

http://forums.macrumors.com/attachment.php?attachmentid=13881

And the rest of us are wrong because we think the 970FX has a Maximum Power Dissipation of 50-55W at 2.0GHz

Phinius

Jun 20, 2004, 06:27 PM

Quick, you better call Apple and tell them their engineers are all idiots and deserve to be fired, because you have the correct numbers for the 970FX at 2.0GHz...

http://forums.macrumors.com/attachment.php?attachmentid=13881

And the rest of us are wrong because we think the 970FX has a Maximum Power Dissipation of 50-55W at 2.0GHz

Then the 2GHz 970FX uses a maximum of 50-55 watts, according to Apple, with a average watt use of half that at 25-27.5 watts according to your calculations. The 25% higher frequency 2.5GHz 970FX uses an average of 50 watts ,according to IBM, and a maximum of 100-110 watts according to the doubling of average watt use formula. So, that's a 1-to-4 ratio for percent of frequency increase to percent for maximum or average power use increase. Then a 20% boost to 3GHz should produce a maximum of close to 200 watts, according to the 25% higher frequency produces a doubling of watt usage formula above. Then, if the POWER5 based core PowerPC chip uses an average of 25% more watts than a 3GHz 970FX chip at the same MHz, then it should use a maximum of 400 watts and an average of 200 watts according to your method of deriving at maximum power usage.

That proves it. Your right and I am definitely wrong.

shawnce

Jun 20, 2004, 06:54 PM

The 25% higher frequency 2.5GHz 970FX uses an average of 50 watts ,according to IBM, and a maximum of 100-110 watts according to the doubling of average watt use formula. What shows that the 2.5GHz 970FX runs at a 50W average. You have a document from IBM?

Phinius

Jun 20, 2004, 07:01 PM

What shows that the 2.5GHz 970FX runs at a 50W average. You have a document from IBM?

That's from the Infoworld article that I have a link to a few posts above.

shawnce

Jun 20, 2004, 07:19 PM

Then the 2GHz 970FX uses a maximum of 50-55 watts, according to Apple, with a average watt use of half that at 25-27.5 watts according to your calculations. Note IBM's own quick reference guide lists the 970FX with a typical power usage of 24.5W @ 2GHz.

ever

Jun 20, 2004, 08:02 PM

How come I'm not seeing anything about the National Educational Computing Conference? NECC kicks off tomorrow... Apple has a huge presence there. The booth is the largest on the floor, and all the booths surrounding it are Apple companies or Apple friendlies. Apple has a whole site for NECC http://www.apple.com/education/necc/

shawnce

Jun 20, 2004, 08:08 PM

SPEC has posted P4 3.4GHz, 1MB L2 cache, scores of 1432 for SPECint and 1481 for SPECfp. Which means that for a maximum watt usage of 27% more than the 2.5GHz 970FX, Prescott has a 29% higher SPECint score and a 8% greater SPECfp posting.

I think your math is off unless I am missing something (assuming you used my numbers and the ones you listed).

So lets say...
970FX @ 2.5GHz does 1100 on SPECint and 1340 on SPECfp
P4 @ 3.4GHz does 1432 on SPECint and 1481 on SPECfp

P4 is 30% faster on integer math and 10.5% faster on floating point (as a side note the clock rate difference is 36%). I cannot check your math on power difference because I don't know what numbers you used.

Anyway if you want to do this comparison (not that I agree fully with its merits) you should normalize using power to make things easier. Since I don't know the power numbers you used lets just say the 970FX uses 1 unit of power and P4 uses 1.27 units of power (27% more). Using these numbers divide the SPEC scores by the units of power and you get...

SPECint: P4 1127.6 & 970FX 1100 -> P4 does 2.5% better int math per unit power.
SPECfp: P4 1166 & 970FX 1340 -> 970FX does 15% better fp math per unit power.

So I don't think the numbers above fully support your statement: So again, if a doubling of average watt usage to achieve maximum watt use for the 970FX is to be believed, then the 970 is about as wasteful of watts per output as Prescott..

It is very hard to do useful comparisons between differing CPU architectures (note the P4 has a double pumped ALU and 970/FX has an additional FPU and those are likely the core sources of the differences in the base SPEC scores).

Anyway doubling the typical power isn't always correct but it allows one to ball park things and it roughly jives with typical to max power deltas seen in IBMs specs. You can however totally ignore the max numbers and not do the doubling like I did in my posts, it won't change the results it will just cut all of them in half.

Also note typical/max numbers from one vendor can be calculated/measured in totally different ways, to such a degree that direct comparison is often not useful. You really need the detailed thermal/power specs to make a good comparison.

Again to bad IBM doesn't list consistent and complete specifications for their CPUs publicly (I prefer to use spec sheets or quick reference guides over any thing said to a reporter or as seen in marketing slides).

Phinius

Jun 20, 2004, 08:16 PM

Note IBM's own quick reference guide lists the 970FX with a typical power usage of 24.5W @ 2GHz.

I ran across a PDF file in IBM's technical library that does list the 2GHz 970FX at an average watt usage of 24.5 watts. Comparing that to the maximum 55 watts that Apple states is a doubling of power use. So that shows that I am wrong there. But, if the frequency is increased by 25% to 2.5GHz, then the average power use should rise to ~30 watts, and a doubling of that would be ~60 watts and not 100-110 watts. That would be a maximum of .909 watts per mm^2 compared to 1.133 watts per mm^2 for the 3.4GHz Pentium 4 Prescott. If there is a 2.5GHz 970FX now in production by IBM, with an average of 50 watts, then it might very well be a overclocked version intended only for Apple's use.

Phinius

Jun 20, 2004, 08:26 PM

I think your math is off unless I am missing something (assuming you used my numbers and the ones you listed).

Since it's very unlikely that the 970FX doubles the average amount of power use going from 2GHz to 2.5GHz or goes from a maximum of 55 watts at 2GHz to 110 watts at 2.5GHz, then my conclusions are wrong. It's more likely that the 2.5GHz 970FX uses closer to 25% more watts than the 2GHz, rather than a doubling from 24.5 to 50 watts. There is a 50% increase in frequency going from 2GHz to 3GHz, and if that also increases the maximum power use listed by Apple for the 2GHz 970FX by 50%, then the maximum for a 3GHz 970FX would be about 82 watts. Which is about 65% of the 127 watt maximum use for the 3.4GHz P4 Prescott processor. That sounds more realistic.

Sun Baked

Jun 20, 2004, 08:34 PM

Since it's very unlikely that the 970FX doubles the average amount of power use going from 2GHz to 2.5GHz or goes from a maximum of 55 watts at 2GHz to 110 watts at 2.5GHz, then my conclusions are wrong. It's more likely that the 2.5GHz 970FX uses closer to 25% more watts than the 2GHz, rather than a doubling from 24.5 to 50 watts.Hmmm...

Maybe you'll believe this source as to the accuracy of the 50W Typical Dissipation for the 2.5GHz 970FX.

Since you don't really trust anyone else... :rolleyes:At the International Solid State Conference (ISSCC) an IBM spokesperson stated an average of 50 watts power use for the 970FX running at 2.5GHz.

http://www.infoworld.com/article/04/02/16/hnpowerdown_1.html

Maxx Power

Jun 20, 2004, 11:21 PM

I'm pretty sick of my computer that heats up this room in the summer, bear in mind this is the basement, and it is plenty cool without the computers, add a G5 and an undervolted athlon (mobile version), this room is on average 4 degrees warmer than the other rooms. How much power can future chips and computer in general dish out before we say "too much" ? I'm not sure how much your electricity bills are, but mine are something around 90 dollars a month, I use all flourescent light bulbs, leave no lights on behind, etc... I remember my first computer (still working), that thing ran cool, never produced more heat than a small desktop stereo system. With all of today's advanced manufactoring technologies such as SOI, strained silicon and low-K, why are there no processors that perform well AND consume very little ?

ffakr

Jun 21, 2004, 12:38 AM

why are there no processors that perform well AND consume very little ?

There are plenty of processors that perform well and don't consume much power. The Pentium M processors perform well considering their thermal output.. as do G4s (as long as they aren't pushed too far in clock speed). Transmeta chips run extremely cool compared to other contemporary processors at similar clock speeds. Heck, Durons perform very well and they are quite cool.. I built a 1.8GHz duron system into a Mac IIci case and it hardly generates any heat at all. My Duron runs as a game server.. I can run a dedicated BattleField Vietnam server and a dedicated Unreal 2004 server at the same time and the machine doesn't break a sweat.

I think the problem is, you are looking for cutting edge performance not a processor that performs well at a reasonable performance level. CPU performance is like anything else.. when you push to the top levels, you push everything else up geometrically. Look at cooling requirements.. Overclockers move from good Aluminum coolers to Big copper coolers as they push the cpu. To go higher, you start monkeying with the core voltage and you start requiring more exotic cooling like liquid systems, compressor systems.. and then you'll even see people putting towers of liquid nitrogen on the cpu to push it even farther.

Maxx Power

Jun 21, 2004, 01:15 AM

There are plenty of processors that perform well and don't consume much power. The Pentium M processors perform well considering their thermal output.. as do G4s (as long as they aren't pushed too far in clock speed). Transmeta chips run extremely cool compared to other contemporary processors at similar clock speeds. Heck, Durons perform very well and they are quite cool.. I built a 1.8GHz duron system into a Mac IIci case and it hardly generates any heat at all. My Duron runs as a game server.. I can run a dedicated BattleField Vietnam server and a dedicated Unreal 2004 server at the same time and the machine doesn't break a sweat.

I think the problem is, you are looking for cutting edge performance not a processor that performs well at a reasonable performance level. CPU performance is like anything else.. when you push to the top levels, you push everything else up geometrically. Look at cooling requirements.. Overclockers move from good Aluminum coolers to Big copper coolers as they push the cpu. To go higher, you start monkeying with the core voltage and you start requiring more exotic cooling like liquid systems, compressor systems.. and then you'll even see people putting towers of liquid nitrogen on the cpu to push it even farther.

Problems with suggested processors:
Pentium M's have few motherboard supports on the desktop side, and if speeds ramped to 1.7+ Ghz, you are talking about 27+ watts of power consumption, a PPC970FX consumes about that at 2 Ghz, hardly is the Pentium M designed for power savings.

G4's have severe problems reaching faster processor speeds, and is a poor general purpose processor as the floating point unit is worse than that of the P4's. This chip is originally designed to be a signal processor for companies like Cisco, who is the dominant purchaser of this processor. They generate significant amount of heat per unit performance compared to the already toasty Athlon's (there are 45 and 35 Watt versions avaliable)

Transmetas is more of an exotic cpu, with low power consumptions but poor performance, even for a non-cutting edge chip. Once again, there is no avaliable motherboard for this chip on the desktop side (imagine a dualie with transmetas!)

Durons consume enough power that I wouldn't call them power-saving. They are basiclly Athlon's with some L2 chopped off (and L2 doesn't consume much power at all).

In response to what you speculated that I desired, why can't there be, say a Pentium M or G4 manufactured on SOI, Low-K and Strained, with chip taken from the center of the wafer, ran on sub 1 volt core voltage, and passively cooled ? Besides the fact that corporate air-heads don't think its worth the effort, I don't think there is any other real challenge to this. The day that happens, I won't feel as guilty being part of a society that consumes 90% of the earth's resources and gives back so little.

ffakr

Jun 21, 2004, 09:42 AM

Problems with suggested processors:
Pentium M's have few motherboard supports on the desktop side, and if speeds ramped to 1.7+ Ghz, you are talking about 27+ watts of power consumption, a PPC970FX consumes about that at 2 Ghz, hardly is the Pentium M designed for power savings.
You're still asking for too much though. You ask why you can't get a processor that "performs well" but you are talking 2GHz PPC 970 and 1.7+ GHz Pentium M's. Your metric of "performs well" is basically the same as 'close to the top of the current performance ladder'.
What you are really asking is, why can't I get a spotlight that uses the power of a nightlight? I would think the answer is obvious.

G4's have severe problems reaching faster processor speeds, and is a poor general purpose processor as the floating point unit is worse than that of the P4's.

By what metric is the G4 a worse performing floating point processor than a P4? On overall performance, perhaps the best metric.. yets a 3+ GHz P4 is a faster floating point processor than a 1.5 GHz G4. Does the G4 have better performance per clock? I believe it does. More in a second..

This chip is originally designed to be a signal processor for companies like Cisco, who is the dominant purchaser of this processor. They generate significant amount of heat per unit performance compared to the already toasty Athlon's (there are 45 and 35 Watt versions avaliable)
This isn't true. Apple had a significant amount of input into the G4 design. Apple was presented with two divergent roadmaps for PPC design, one in which IBM promised high frequency processors and one in which Moto promised a robust vector engine. IBM figured their work on their proposed processor would be useful in other areas of their PPC research, and Motorola also figured that the markets they were also targeting would benefit from a fast vector engine.
I think it's unfair to say that the G4 was designed for the embedded market and NOT for Apple. The G4 was designed for Apple with the full knowledge that it would fit into certain embedded markets well. The problem for us Mac users is that Moto decided down the road that they didn't care all that much about desktop performance and they made deliberate design choices to make the G4 a better embedded processor to the detrement of it's performance in the desktop space. One of these choices was to design for low power consumption OVER all out performance (making it the perfect chip for what you are looking for). A PPC 7457 @ 867MHz runs is rated at ~ 8 typical / 11 max watts and at 1 GHz it's rated at 15 typical / 21 max watts. That's not bad for a processor that will easily run productivity apps, run movies.. do a lot of common computing tasks. I'm running a Quicksilver 867MHz and I'm at a loss for any compelling reason to ask for an upgrade. The machine (with enough memory and a Radeon 9000) does just about anything I need it to do and it will play all but the most intensive video games.

Transmetas is more of an exotic cpu, with low power consumptions but poor performance, even for a non-cutting edge chip. Once again, there is no avaliable motherboard for this chip on the desktop side (imagine a dualie with transmetas!)
Again, you haven't given us any guidance on what you expect out of a processor that runs "well". Transmeta's, last time I checked, did a decent job of keeping up with P3s at roughly the same clock and a 1+ GHz processor is decent performing by my measure.. especially considering how little heat they put out.

Durons consume enough power that I wouldn't call them power-saving. They are basiclly Athlon's with some L2 chopped off (and L2 doesn't consume much power at all).
True, a duron is just a cut down athlon, but I've owned a few over the years and they always draw appreciably less current than their big brothers. I say this annecdotally based on the amount of waste heat they put out and how slow they run the fans in my variable speed power supplies. My Athlon machine always spins a 300W Antec up full speed and my current gaming server (a 1.8 GHz Duron with a 300W Antec.. in a Mac IIsi case.. barely spins the power supply fan and it generates very little heat in the case.

In response to what you speculated that I desired, why can't there be, say a Pentium M or G4 manufactured on SOI, Low-K and Strained, with chip taken from the center of the wafer, ran on sub 1 volt core voltage, and passively cooled ? Besides the fact that corporate air-heads don't think its worth the effort, I don't think there is any other real challenge to this. The day that happens, I won't feel as guilty being part of a society that consumes 90% of the earth's resources and gives back so little.because the companies that make those ships don't have all of those technologies. I believe that IBM is the only company that is currently using Low-K, SOI, AND strained silicon in the same fabrication process. Also, what you are asking for is a very selective sort. It would mean the chip would command a high price, at which point you'd probably be lamenting about how the corporate air-heads don't know which side is up becaue they want a fortune for your sub 1 volt, 2 GHz sub 10 watt processor.

macridah

Jun 21, 2004, 12:32 PM

I wonder how Apple could use liquid cooling technology on a 1U xServer? Maybe they might have to implent a 4 way-4U server (maybe 3U). That will be the quad macs people have been speculating.

Maxx Power

Jun 21, 2004, 01:00 PM

Quotes are getting long, I'm skipping them and going to the point instead.

1) I'm not asking for either 1.7+ GHZ Pentium M's or PPC970FX at 2.0 GHZ, i'm simply constructing a situation where Pendium M, a chip we know by intel marketing that should be a low power chip, isn't.

Also, spotlight that uses the power of a nightlight is oversimplifying my statements. A correct analogy would be a desklamp that uses the power of a nightlight, or a flashlight that uses the power of an LED, both of which are now possible thanks to LED (which by the way, was held back by massive marketing funds poured into the old fashions of lighting, and is only now seeing light, i bought my first LED flashlight on Ebay 4.5 years back).

2) By PURE floating point unit (FPU) comparison. For a glimpse of what i said here, refer to http://arstechnica.com/cpu/01q4/p4andg4e2/p4andg4e2-3.html
Understand that by design, the G4, and G4e were never meant to crunch floating points.
If you quote me numbers on crunching filters in Photoshop, please stop. Even adobe is sick of apple's distortion field and I believe back a while there was a link on this very website that shows adobe pointint out that a 3.0 Ghz P4 with hyperthreading is faster than a dual 1.42 MDD.
However, marketing arguments aside, the numbers posted at SPEC.org and the following tests using photoshop http://www.digitalvideoediting.com/2002/07_jul/features/cw_macvspc2.htm
both support my theory that the G4 is overhyped and underperforming.

3) But of course Apple would have significant inputs to the G4 design. After all, Apple is the Second biggest purchaser of these processors in volume. You'd think if apple had significant inputs actively and proactively (telling them what to do, and moto would oversee what might be needed and modify the cpu design), then the biggest buyer must have had even bigger inputs. If you go to moto's website, you'll see that these processors are shown and listed http://e-www.motorola.com/webapp/sps/site/taxonomy.jsp?nodeId=03C1TR04670871
is described by the manufacturor to be embedded use. Just look at the fact that Moto is in no way appears to be pressured by Apple when apple demanded faster clock speeds shows that they are happy with the processor because it is selling well to the primary customer - Cisco and subsidiaries.
If the manufacture of these CPU's categorize them as embedded, then I guess whether they intended to or not design this for embedded, it is by definition an embedded, this, of course, offers indirect evidence of what i said about these processors are designed for. Either way, the means aside, the ends are the same.

You mention of the fact you are able to play games with your system. But of course! Only that games run the way they are on newer systems to stimulate the hardware industry. Now, I don't support that bit, I don't think the market should be a closed loop system where purchasing something should entice you to purchase another object in a closed-loop fashion, it almost sounds like scam. There is no reason why new games can't be optimized to run as good as the previous gen, at the same time offer new things. But getting back to the point, a G5 1.6 Ghz with a ATI Radeon 9600 pro can only struggle out 20+ fps in UT2004 (i guess this would be a hardcore game, so this doesn't go toward your statement, i'm just making mention of this anyway) at ANY reasonable resolution and settings. This is because the frame rate is limited by the CPU, not the GPU. The CPU on this particular mac has to process all game AI, network, AND mix sound streams. Translation, this particular Mac lacks hardware ethernet and hardware sound. This has been the case for as long as I looked at the problem and is continuing.

I agree with you that your 800+ Mhz processor is fast enough to deal with most situations. What would be even better is if you had a 1.6 Ghz, then have some kind of speed-step (my fav) technology on it, so you can run it at 500 mhz for DVD's, or 1.6 for encoding, or 100 mhz to leave the computer on over night to download something, there is no reason either why that should not happen. I was happy with my previous pIII laptop that had this feature, you could program it to run at any frequency and bus frequency (almost any), and shut down parts of the CPU when not in use (optimizations, mostly). I guess its because most northamericans are wasteful, so the similar situation happens in cars as well. We all know the in new cars the cylinders fire using computer programmed timed-detonation. With a simple programming, you can set up so that you V8 skips injection and detonation of every second cylinder, hence effectively a V4, or better yet, you can go further, and bring it down to a V2. You won't haul with that, but in idle, who needs all 8 to be firing ? In everyday city driving, on average, firing 6 to 5 cylinders is sufficient, this brings down gas consumption and emissions, and it requireds very very minimal change to the current engines, but like i said earlier, the corporate air-heads would make you believe this CAn't be done through their awesome power of the marketing. We all know the vehicle industry doesn't try to improve anything unless a huge demand is on them, just go read http://journeytoforever.org/biodiesel_404.html and Ralph Nader's book from the 1970's i believe called "Unsafe At Any Speed" and know that the president of GM at the time had to publicly apologize to Nader for harassing him and spreading untrue rumours...

4) My performance measure is something that will run everything I run now. My REAL performance measure is having a new generation of chip that performs better than previous at the same clock speed AND consumes less power. That would be a win-win situation.

5) I personally don't find earlier durons to consume much power, they were quite a bit better, I haven't used a duron since then.

6) Corporate cross-licensing is possible. Costing a bit more is nothing compared to the devastation of the environment. Can 500 dollars U.S. buy you back the rain forest ? Can your precious money buy you clean oceans ? This just goes to show the typical ignoranc attitude among our communities. And being part of the corporate externalizing, money rolling machine, the corporate goons have one real reason for anything they refuse to do - it will cost them some money. How much more can such chips be ? Manufacturing processes have matured since the first days of CPU's and bigger wafers reduced the cost per chip, and yet, these CPU's still cost anywhere in the few hundreds in the retail markets. Where did all the money saved go ? Obviously it went to profit instead of seeing the light of the day with the customers. Just look at the CD situation, cd's used to cost a bit to produce, but now they literally costs pennies a CD to be printed, and still, they prices are same as years ago, hovering around 20 dolllars a CD. The actual manufacturing price of a chip with multiple advanced technologies isn't expensive, it's just that when you add margins like the backfat of a pig, any lean meat is turned into bacon.