More Dual PowerPC 970 Info...

[nuckinfutz]

Do you really run all this Apps together every day ? Wouldn't you prefer to run one of then but much much faster instead of 3 of them at you current speed?
If I'm editing some movie I won't be doing heavy Photoshoping. Maybe open one file and make some light changes. I would much rather see the end of the progress bar then being able run more at once without sacrificing current speed.

You overestimate the speed increase from shutting your apps down. It really depends on your workflow but I know plenty of people that routinely have multiple apps open so that they can quickly access Photoshop to tweak graphics before importing into Final Cut. Multitasking is the future the preferred OSX method is to have a lot of RAM and just load up your applications.

a single processor running at a high clockrate ala a Pentium 4 is suited for running one app quickly.

SMP systems don't run as fast generally but they multitask so much better so they can be faster when you've loaded your system up with apps and processes.

 

[Pedro Estarque]

I'm just saying that the more Proc. you have the harder it is to spread the threads in a efficient way. One info might be in the first Proc.'s cache and is being needed in the fourth. I have 202 threads running right now, its not like you could split 202 ÷ 4 :
1º 970 -> 51
2º 970 -> 51
3º 970 -> 50
4º 970 -> 50

And make it run 4x faster.
Otherwise Apple could just gather some PPC 604e and make a 256 processor machine that would kill anything for a really nice price.

 

[Pedro Estarque]

You overestimate the speed increase from shutting your apps down.

Photoshop benefits a lot from free RAM. So running it alone leaves more memory to it and the speed is quite noticeable.
I run PS next to safari, mail and itunes every day. When I start Dreamweaver, Toast , iMovie etc I can see some sluggishness in PS. Specially in the first few minutes after switching from other apps. It takes more time to switch from app to app. UNIX is great, but RAM is a finite resource and the more Apps running the more you'll be hitting the HD. There's no magic. OS X does a much better job doing lots of things at the same time then OS 9 did, but memory intensive applications such as PS will run faster if running alone.

 

[Frobozz]

I disagree.
If they make Tiger highly threaded...
Imagine. You run Photoshop CS, Final Cut Pro 4, and Maya3D all at the same time.
Since Tiger is threaded, it allocates the programs-
Processor 1: OS X core system processes
Processor 2: Photoshop CS
Processor 3: Final Cut Pro 4
Processor 4: Maya3D

Even if Photoshop, Final Cut Pro, and Maya WEREN'T multithreaded, Tiger itself (being a multithreaded OS) would give each program it's own processor.

Result? Speed boost, baby!

Well, I don't know. Maybe I'm wrong, but unless you are a very fast individual I don't think you can use all 4 simultaneously. Even then, if you set them up to render something all at the same time, you'd probably be better off just having one app open and letting 4 logical processors render frames: cpu 1 does frame 1, cpu 2 does frame 2, etc.

 

[JoePike]

Dual Duals

I definitely think that Steve and the kids down in Cupertino will not shy away from putting dual dual-core processors in a powermac. They did it with the new graphics cards, didn't they? The 6800 provides the dual-DVI necessary for the 30" display, and you can plug in two of those at once if you want, right? This is a company that has a history of trailblazing and leading the way by "thinking big". Steve-o also likes turning heads, and a computer with a total of 6+ ghz of computing power would certainly turn some heads.

-Joe

 

[nuckinfutz]

I'm just saying that the more Proc. you have the harder it is to spread the threads in a efficient way. One info might be in the first Proc.'s cache and is being needed in the fourth. I have 202 threads running right now, its not like you could split 202 ÷ 4 :

That article already combats that. With ondie cores the cpus can snoop each others cache without traversing the FSB. The latency and bandwidth improve greatly. Code Cracking allows for the instructions to benefit from this increase in bandwidth and latency between cores by cracking the insruction in have and processing simultaneously. The kernel handles the threading, there is no need to split the threads evenly amongst 4 cores. Some threads are more demanding than others. The kernel handles these in in the best way possbile. Remember Tiger will have improved SMP performance with fine grain locking. Targetting and managing multiple threads will be improved over what we have today.

Photoshop benefits a lot from free RAM. So running it alone leaves more memory to it and the speed is quite noticeable.

Yes it does. Photoshop is a poster child for how NOT to do your memory management. We can only hope that they rewrite the next memory management in PS to support 64bit memory and get rid of the 2GB RAM limit. Adobe rolled their own scheme and it's getting a bit long in the tooth.

 

[~Shard~]

Will everybody please stop repeating this nonsense about this being the end of dual processor Macs.

Why it is nonsese? Do you know for a fact there will always be DP PowerMacs? Sound pretty confident in yourself...

A dual-core is nothing but two processors on one chip, there are still two processor cores in the computer. The OS and all programms will see two processors, you will even have a somewhat better performance than with a two processor computer.

You don't have to tell me this, I already recognized and appreciated it in my post.

If you think that the wide public and maybe yourself would perceive a dual-core Powermac as somethink less powerful than a dual-processor Powermac, you should for once accept that the opposite is the case and also rest assured that Apple marketing would try its best to correct that impression.

I don't. You should read posts a little more closely, I never once even suggested this. In fact, I completely agree with you, and since I used to focus on microprocessor ansd ASIC design, I probably know the relative power and performance attributes even more in depth than you. A word of advice - people don't like it when you put words in their mouth, so I don't know why you were stating all of this by quoting my post...

 

[maxvamp]

My Prediction..

While I know that many if not most apps out there are MULTI-THREADED, I will concede that there is a practical limit of usefulness for multiprocessing. After all, will a 16 way system really buy you much more power than a 4 way when doing Photoshop?

I doubt it.

My prediction is this:

The chips will not only be dual core, but will be SMT enabled. In the Powermacs, there is more of a need for space. In the XServe, there is more of a need for raw power.

I suspect, that the PowerMacs will be reintroduced as a single chip, single or dual core processor, and some extra drive bays / PCI (x?) slots thrown in. On the more server centric side, I could see the XServe being a dual chip single or dual core proc running at a lower speed and maintaining the same form factor that they have now.

This is my opinion based upon nothing.

Max.

 

[AidenShaw]

Naive understanding of threading...

If they make Tiger highly threaded...
Imagine. You run Photoshop CS, Final Cut Pro 4, and Maya3D all at the same time.
Since Tiger is threaded, it allocates the programs-
Processor 1: OS X core system processes
Processor 2: Photoshop CS
Processor 3: Final Cut Pro 4
Processor 4: Maya3D

Even if Photoshop, Final Cut Pro, and Maya WEREN'T multithreaded, Tiger itself (being a multithreaded OS) would give each program it's own processor.

Result? Speed boost, baby!

Dedicating threads to CPUs works until you have as many threads as CPUs. Dynamic scheduling works much better - as threads request CPU they are scheduled on a free one. If FCP has 4 threads requesting CPU, it should get all 4 CPUs rather than being restricted to Processor 3 as you suggest.

Right now my XP system has 61 processes and 1133 threads....

 

[gerrycurl]

dual cores are great

I can't wait for dual cores!

 

[G4-power]

The Red Wolf.

Exactly. I'm suprised at how many writers have commented about how hot the Dual 2.5Ghz chips are without having any empirical evidence regarding the heat max on this cpu. They are basically assuming that the chips are ungodly hot because of the LC system. Well I prefer to think of it as over engineering for the future.
...
Once 2.5Ghz owners get their computers sometime next week we'll have a better idea on how effective the LC system is and if it's suitable for cooling as many as 4 cores.

Yes, indeed. When the multiple forum threads about Rev. B PowerMacs were up, I remember some wattages for PPC 970 and 970fx. IIRC, 970 fx was about 24 watts, and 970 at about 70? ( I don't remember if they were typical or max or whatever) Anways, they didn't actually need LC in the original 2x2 GHz model, and let's say if the wattages were 25 with the fx and, say 40 (@2GHz) with the original chip, a 0.5 GHz boost on speed won't take wattage over 40 with the fx. So it won't need the LC either. But it's okay for me, and I think others too, it makes the computer way quieter, I hope.

As for the 970MP, PowerTune on it? That would help keeping heat generation even lower. So at 3 GHz a single chip dual-core machine wouldn't be a problem, and it shouldn't be at dual chip dual-core a problem either. Just waiting for next Spring to see what'll happen, and hopefully a G5 for my use too! Just hope we'll get a Rev. C or at least speedbump before December. I'd say the deadline is in March, another 12 months without upgrading isn't taking Apple far.
Just my opinion, what do you think?

 

[virividox]

6 more months from announcement till release and another 3 months till shipping

 

[Amdahl]

Amdahl predicts no SMT

Very good, you have recognized the meaning of Amdahl's Law.

But I have to disagree on the SMT prediction. SMT (known as Hyper-Threading on Pentium 4) makes sense if you have a CPU with very few registers, like x86. PPC has at least 4 times as many registers, so the benefit of SMT would be close to zero. It usually has only a few percentage point benefit on Pentium 4/HT.

While I know that many if not most apps out there are MULTI-THREADED, I will concede that there is a practical limit of usefulness for multiprocessing. After all, will a 16 way system really buy you much more power than a 4 way when doing Photoshop?

I doubt it.

My prediction is this:

The chips will not only be dual core, but will be SMT enabled. In the Powermacs, there is more of a need for space. In the XServe, there is more of a need for raw power.

I suspect, that the PowerMacs will be reintroduced as a single chip, single or dual core processor, and some extra drive bays / PCI (x?) slots thrown in. On the more server centric side, I could see the XServe being a dual chip single or dual core proc running at a lower speed and maintaining the same form factor that they have now.

This is my opinion based upon nothing.

Max.

 

[nuckinfutz]

But I have to disagree on the SMT prediction. SMT (known as Hyper-Threading on Pentium 4) makes sense if you have a CPU with very few registers, like x86. PPC has at least 4 times as many registers, so the benefit of SMT would be close to zero. It usually has only a few percentage point benefit on Pentium 4/HT.

If this is true then how do you explain the SMT in the POWER5 which is still PowerPC ISA? While I agree with you the 970MP isn't going to have SMT I think we see SMT on the next major revision(G6 ?). But not for another 12-18 months.

 

[wdlove]

If this is true then how do you explain the SMT in the POWER5 which is still PowerPC ISA? While I agree with you the 970MP isn't going to have SMP I think we see SMP on the next major revision(G6 ?). But not for another 12-18 months.[/QUOTE/)

If it is going to be that time frame for the Dual Core, that is a long wait. Then the problem of not wanting to get Rev. A of a brand new Mac. Just think that if we buy now we will get to enjoy a G5.

 

[manu chao]

Why it is nonsese? Do you know for a fact there will always be DP PowerMacs? Sound pretty confident in yourself...

Simply because a Mac having one chip with two processors (dual-core) is a two processor Mac for me, or a DP Mac to use your expression. So any Mac having a dual-core chip is a DP Mac by definition. That's my main point, the rest is just an explanation why I think that is the way you have to look at it.

One can certainly argue whether a chip with two processor cores counts as one processor (which happens to have two cores) or as two processors. But since it acts as if it had two processors (roughly the same processing power as two individual processors) I see no point in not calling it a dual-processor computer.

I don't. You should read posts a little more closely, I never once even suggested this.

Sorry, that part about the perception was a response to this post:

Yeah,
The trick will be selling these machines with one physical processor to a customer base that has come to believe that dual procs are the way to go for best performance.

I could start a big fight with people claiming that hybrid cars will replace all the gasoline driven cars in the medium term. Not that we might not be driving all hybrid cars in 30 years from now but any hybrid car (as it is conceived today) uses a gasoline (or diesel) engine and is therefore also a gasoline driven car.
The correct way to say this would be that "hybrids will replace all the CONVENTIONAL gasoline driven cars". Naturally, most people discussing this will understand that the first statement implied the word 'conventional' but to people not knowing exactly what a hybrid car is, the first statement could be misleading.

Maybe this helps you to understand my logic.

 

[Amdahl]

Amdahl predicts no SMT

If this is true then how do you explain the SMT in the POWER5 which is still PowerPC ISA? While I agree with you the 970MP isn't going to have SMP I think we see SMP on the next major revision(G6 ?). But not for another 12-18 months.

SMT.

It is very unlikely it will occur in the 970MP, because the power4 did not have it; they wouldn't do a retrofit, so we agree there.

But I think it also quite unlikely to appear in a 'G6' either for a few reasons.

The POWER5 goes into systems (envisioned) to have way more memory bandwidth than a desktop system.

The POWER5 sells for a lot more, and is allowed to suck a lot more power for the intended use.

As I said previously, the benefit of SMT is not great on Power PC, thus, this next point really drives it home:

According to http://arstechnica.com/cpu/003/mpf-2003/mpf-2003-1.html, "The rest of the big changes to the core are related to the addition of SMT, which IBM claims increased the size of each core by 24%. (This increase in die size is another reason why an SMT-capable POWER5 derivative for the Mac is a ways off.)"

24% more chip size is not worth the limited benefits in a desktop.

 

[macsrus]

Die size is interesting

In addition, the PowerPC 970MP will be a significantly larger package than the existing PowerPC 970FX. Compared to the latter, which sports a die size of 66.2 square millimeters, the PowerPC 970MP will spread out over 154 square millimeters

Did anyone notice that the die size is more than double?

I expect that the cache size increase will take up some of the extra space...
But just maybe IBM will add an on die memory controller at the same time...

They did for the Power5
The POWER5 also supports DDR2, with an on-chip memory controller.

Maybe these will be added to the PPC too....

 

[~Shard~]

... ... Maybe this helps you to understand my logic.

Thanks for explaining yourself a little better, I slightly misunderstood your position as well.

 

[zelmo]

Powermac : Dual-Core-Dual-Processor @ 3 GHz
iMac / Powerbook : Dual-Core-Single-Processor
iBook / eMac : Actual G5

????

Yes! Bring them up! Go IBM! Go apple!

I was thinking exactly the same thing, AmigoMac.

 

[nuckinfutz]

The POWER5 goes into systems (envisioned) to have way more memory bandwidth than a desktop system.

The POWER5 sells for a lot more, and is allowed to suck a lot more power for the intended use.

As I said previously, the benefit of SMT is not great on Power PC, thus, this next point really drives it home:

Thanks for the links. I love Stokes' writing on CPUs. Actually after reading this article I'm more convinced now that both dual core and SMT will be on the next major revision and here's why.

The rest of the big changes to the core are related to the addition of SMT, which IBM claims increased the size of each core by 24%. (This increase in die size is another reason why an SMT-capable POWER5 derivative for the Mac is a ways off.)

That automatically rules out the 154mm 970MP. Adding SMT puts the 970MP at nigh 185mm. No go.

Since increasing execution unit utilization is one of the main goals of SMT, the increase in issue bandwidth utilization as described above is going to be key, especially for the POWER5. I say this because in my first articles on the G5 I suggested that the POWER4/970's group-based dispatch scheme and issue queue configuration probably constrains issue flexibility and therefore execution unit utilization in some peculiar ways under certain worst-case scenarios (i.e., one execution unit of a pair is overloaded while the other is starved, due to a combination of poor instruction ordering on the part of the programmer/compiler and the group dispatch limitations)

Another gotcha in the 970. I expect IBM to rectify this not that it's really bad but you don't want one execution unit starved while the other is gorged. I'm figuring that IBM fixing this is a priority.

At this point, I could talk about the need for SMT in an Apple system, but I'll just leave off that sort of commentary for now and observe only that Apple's long-standing and ongoing affinity for SMP designs has resulted in two things: 1) a huge potential for wasted execution resources on the current crop of non-SMT-capable G5s and 2) a body of natively-developed and -ported applications that have been subjected to years of pressure to use multithreading wherever possible in order to wring the best performance out of Apple hardware. I think both of these factors will converge to make a SMT a significant improvement for the Mac platform.

Makes sense. Apple has been actively promoting the use of threading(more than one session at WWDC 2004 on threading). While the 970x processors do not efficiently feed the execution units I'm sure this will not happen with the mythical G6.

I see the plans going like this.

970MP systems ship Q2 2005. There are two refreshes.

IBM works on POWER5 derivative which replaces current execution units in 970x CPU, is also a dual core with SMT and I'm guessing adds an ondie memory controller. This is all at 65nm so we're about 100-120mm squared for the whole shebang.

Apple wants this because

1. SMT will help in Xserve systems
2. Dual Cores are standard now.
3. Ondie Mem controllers allow them to reduce the complexity of the system controllers. 980MP systems will have hypertransport 2.0 links betwen them.
4. Thread prioritization is right up Apples alley being heavy in multi media.

I won't be suprised to see Apple really hammer threading even more for WWDC 2005. It's amazing but large apps like Maya still don't support SMP.

I'm pretty jazzed about the POWER5 queing 10 instructions and dispatching 2 per cycle. IBM need only add this same function to the 980 and get the Altivec unit back to G4+ levels and we'll be sitting pretty by 2006.

 

[Sun Baked]

The marginal increase in size and heat on a Power5-UL would probably mean that they'd drop right into the current PowerMac G5 and provide a 35-40% performace boost (according to IBM).

The dual-core make a bit more sense for dual processor XServe G5s, DP iMac G5s, and a low-end PowerMac (which Apple seems to be moving towards, like the PB12).

IBM did say dual cores were the way of the future, though you "may" have to turn the clock down to keep them within the current heat/power envelope.

Using the 90nm tech, a 1.8/2.0 GHz PPC970MP would definitely make sense in a consumer machine -- especially since you kill all the extra stuff (Power Supply and support chips) needed for the second CPU module.

But then you hit marketing perception -- how would a dual 2.0GHz PPC970MP (4 core) at 90nm stack up to a dual 3.0GHz Power5-UL when there are still 3.x-4.xGHz Pentiums out there. When people still see MHz as the guide to which machine is faster.

Apple/IBM WILL need to compete against the coming dual x86 core CPUs (at lower clock speeds), but the MHz war is still winding down -- they may or may not need to sell both at the same time.

---

While there are technical benefits to going either way (fast single core, lower clock dual core) -- the choice for Apple may come down to which is easier to market/sell in the current MHz marketing climate.

 

[FFTT]

I am SO grateful for these forums. Honestly!

I went by the local Apple store yesterday trying to make up my mind
about finally getting a replacement for my beige G3 tower.

Although I really did like the PowerBooks. I felt that spending so much
for G4 technology this late in the game was setting myself up for disappointment in the all too near future.

The 2.5 G5 dually seemed to be a much safer long term bet, but spending
$3400 for the CPU alone sent me back to the think about it stage.
Adding a 20" display and a Protools LE interface and I would be in rather deep.

Reading this thread now makes me very glad to wait just a bit longer.

This is not just a CPU speed increase, this is a MAJOR difference.

 

[tych0]

More dual core benefits

Hey all

To those that say that multiple cores won't bring speed-ups to some applications, it might be good to point out that much of OSX already distributes some of its API calls on multiple processors. For example, Core Audio is multithreaded. Cocoa apps and games that call that library, for example will benefit from having multiple processors, even if they weren't written to take advantage of them.
As for Photoshop, is _has_ run well on 4-way systems in the past (4x Daystar Mac clone, back in the day), so it shouldn't be too much of a stretch to get it working very well on those systems.
Not what I would REALLY like is a return of the Cube... single-processor, dual core, maybe an inch larger to accomodate recent graphics cards... At the price point of a headless iMac... I can dream, can't I?

My 0.02$ worth...

 

[wdlove]

Though with the G5 being a new technology the recommendation was to wait for Rev. B. It seems that there is possibility dual core is due to be released at MWSF '05. If so that means that the Rev. B, would mean waiting a least another year.