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PowerMac DDR Clarification

Re: Re: Re: a little help from my friends...

Originally posted by cyberfunk


MY bet on the big heat sink is that they're using a larger, slower fan, so it's more effective to have a larger surface area.
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Don't say that! Say it's for a G5, damnit! :)

Maybe if we wish hard enough, we can make THESE Power Macs the G5s! Come on everybody, let's do it. "I love these new Power Mac G5s!" Everybody now. "I love these new Power Mac G5s." Mind over matter, people!
 
CPU upgrades on new PM's?

I'm looking forward to hearing from folk with the new PM's as to whether or not the CPU's are soldered in or not. I presume if they're soldered upgrading the CPU becomes a hell of a lot more complicated for those of us who have never soldered electronic components before, let alone even own the appropriate soldering iron.

Also, if the son of Power4 draws significantly more power than the PPC 7455, won't that require some other adjustment that most consumers are not up to doing? Does anybody have any educated guesses about the pin count/sockets of junior also?

I'm not too bullish on this upgrade speculation, though a rather learned person on arstechnica believes an upgrade to a 7470 or some other 74xx w/ native DDR capability is quite probable. It would still require soldering and over-clocking, however.

Eirik
 
Re: Re: a little help from my friends...

Originally posted by eirik
I'm stretching my understanding of these things here so please be kind oh EE-enlightened folk.
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The only thing an EE would tell you is you may be looking at the wrong end of the problem and making it way more confusing.

Everyone is focusing on the FSB (between the controller and the CPU), focus on the datapath between the memory and controller instead.

There is much more memory bandwidth here on the DDR path for the system controller to share via DMA processes. You have the CPU, AGP card, PCI cards, and the primary & secondary ATA buses all fighting for their share of memory's bandwidth.

Even if you give the FSB all the data it wants, there's still enough bandwidth left for the rest of the DMA requests.

Looking at it this way it might not sound so bad, but a slow FSB also limits the maximum number of operations the CPUs can handle - and the PPCs are a lot hungrier per clock cycle than the avereage wafer. And you're trying to feed two of these little beasties.
 
Re: Question

Originally posted by alex_ant
We know that the new Power Mac has a crippled DDR implementation. Could the 7455 CPU module in one of these systems be replaced in the future with a different CPU that DOES support DDR, thus un-crippling the memory architecture?

In other words, was DDR hacked onto the motherboard in order to achieve a real performance increase, or was it hacked onto the motherboard in order to facilitate future CPUs and their respective modules that would be able to truly exploit it, providing an upgrade path to a certain future DDR-compatible PowerPC chip?

Alex
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Apple has officially stated (in confidence) thatthe current box is G5 compatible FWIW.

Jerry
 
Re: Re: a little help from my friends...

Originally posted by alex_ant

If your only consideration is performance, then if you could find the old DP 1GHz for substantially less money than the new one, I would go with that. I would be very surprised to see more than a 5% performance difference between new and old. The new system has a hacked DDR implementation the same as the Xserve, with the same CPU (MPC7455) as both the Xserve and the old DP machine. Various performance benchmarks between the old DP Power Mac and the DP Xserve revealed virtually no performance difference, indicating that this crippled DDR implementation does little to nothing to enhance performance.

HOWEVER (and the following is only speculation), the new case of the new Power Macs may be a hint at some sort of possible upgrade to this Power4-derived PPC we're all waiting for. It would make sense - why give all this cooling and ventilation to a G4 system that doesn't need it? Still though, I would buy the old G4, because there's always eBay.

Alex
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While I find each use of the word "crippled" appropriate, I remind you that the throughput and the Gigaflop rating is about double. That matters.

Alot.

Rocketman
 
Frame rate?!?!

Originally posted by topicolo
Play Quake 3 at 1600x1200 with 4x FSAA at a reasonable frame rate :)
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Try play WarCraft 3 with 1600x1200 and all the option set to high, let see what the frame rate you're getting
 
So we know the previous 1ghz duallies ran up to 15 gigaflops according to apple.. the new 1.25ghz with ddr ram and 167mhz fsb run up to 18.3 gigaflops, so we know there is an improvement..

but I want to know what the new 1ghz duallies with 167 bus and ddr will do... or even still, what the xserve will do, since it's very similar to the new mid powermac (aside the 167mhz)

I'd hope the new dual 1ghz would do at least 15gflops, like 16 or so, but I'd like to see that spec!
 
One thing I found interesting and helpful in my purchasing decisiong is what I read on arstechnica...

one guy mentioned that since the mobo's are the same all accross the line, it shouldn't be much to overclock the dual 867 to have a 167mhz bus and the cpu to 900 somthing.. (can't remember the exact multiplier) It sounds feasible, espescially considering the ibooks that can be overclocked via software from 600 to 700mhz!!!

Aren't there utilities that will over clock bus speed??
 
Originally posted by soilchmst


since Quake 3 is optimized for dual proccessors and the Geforce Ti is pretty damn fast and can access the the DDR directly, wouln't Q3 run stellarly? ;)
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not nearly good enough to make 60fps, even on a 2.54Ghz P4. The 4xFSAA actually downsamples the images from a resolution 4x greater.
 
It's so nice to see people taking a typical Mac OS 9 style test and saying, see the new machine is NOT faster.

Too bad these tests are not real world for OS X.

With the multithreading we all know a lot of these single actions are slower, but the machine is also doing MORE at the same time.

Where are the real OS X tests?

Where are the true tests of the multi-tasking capabilities? Such as Photoshop&Quake Frame Rate, Photoshop&Storage Testing, etc.

Nobody is really showing the true capabilities of the machines, nor the new buses.

Here let me pat you on the head for blindly swallowing this single action OS 9-style line of BS. (PAT, PAT, SLAP)
 
Originally posted by Sun Baked
It's so nice to see people taking a typical Mac OS 9 style test and saying, see the new machine is NOT faster.

Too bad these tests are not real world for OS X.

With the multithreading we all know a lot of these single actions are slower, but the machine is also doing MORE at the same time.

Where are the real OS X tests?

Where are the true tests of the multi-tasking capabilities? Such as Photoshop&Quake Frame Rate, Photoshop&Storage Testing, etc.

Nobody is really showing the true capabilities of the machines, nor the new buses.

Here let me pat you on the head for blindly swallowing this single action OS 9-style line of BS. (PAT, PAT, SLAP)
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Would you mind elaborating on how the Barefeat tests were not realistic and were OS 9 centric? I don't understand.

I looked at the test details and it implied that the Photoshop test was version 7.0 so that it would take advantage of 7.0. I don't know about the Bryce and mp3 (iTunes) tests, however.

Seriously, I don't understand and your post sounds very provocative, like something that I'd like to know too.

Thanks,

Eirik

BS. I emailed Rob over at Barefeats, asking him to run tests with larger files as well as video tests so that we'd see results of tests that were far more memory intensive than the 30 MB PS 7.0 test.
 
Eirik,

Under Mac OS 9 you might do each of his tests, listed under "How I test" as a single action - only due to the fact that some of these actions would suck up so much CPU time that doing several at the same time would make GUI rather slow to respond, and you made allowances for this.

Because some of the programs were such hogs you might do something like start a rendering job and go get a cup of coffee. Plus under OS 9 there were a lot of applications that plain would never use the second processor - it just sat there with nothing to do.

But under OS X, the entire system and the applications are designed for SMP and multithreaded to the point where doing multiple tasks at once is becoming the norm.

So basically under OS X, it's a better indication of how the machine/OS works if you do something that stresses the CPU/memory/video/storage in a combination that would test 2, 3, or 4 of these at the same time.

I'm adding this link, because these guys can say it a lot better than I, why these OS 9 style test are pointless on a OS X system.

http://arstechnica.infopop.net/OpenTopic/page?a=tpc&s=50009562&f=8300945231&m=9600944035

Dragoth really lets him have it. :)
 
which os/version was used??

Originally posted by Hemingray
Hey guys, if you want some disturbing info, check out BareFeat's new benchmark test comparing the old dual 1GHz with the new DDR dual 1GHz!

http://www.barefeats.com/pmddr.html



Ouch! :eek:
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Did I miss something? I don't see where it says which OS he used..and if he used OS X, did he use Jaguar? That would see most appropriate, since it is the newest and most revelant OS/version.
 
New G4 Block Diagram

Here is a block diagram of the new PowerMacs (from the service manual):
 

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Re: Re: Question

Originally posted by Rocketman


Apple has officially stated (in confidence) thatthe current box is G5 compatible FWIW.

Jerry
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Where has apple stated that this machine is G5 compatible? The only thing I have seen saying anything like that was that PDF someone made up describing the new tower features. The only way you could see the G5 upgradeable in that PDF was to move an image that was overlying it revealing the alternative header.


My question is, does anyone know where the FSB resides within the machine? Is it on the CPU card or is it on the motherboard? If it's on the motherboard I don't see how all the G4 7470's and G5's in the world would give you true DDR. Seeing how the bottleneck and lack of true DDR support is not only in the current CPU's but because of the CPU the FSB is also limited. So you have to not only replace the CPU but also the FSB.


I don't know about anyone else but I've been running a B/W G3 400 for too long now and have already ordered the new Dual 1gig it doesn't matter if it's not a G5 it's a revolutionary jump for anyone still running a G3 and some that are running G4's.

I personally really like the new case and I want to settle a few disputes that people are having but have been answered many times but they haven't heard.

1. People keep saying this isn't truly the prototype case we all saw because the prototype was white.

A) The prototype was not white but still silver the people who took the pictures of the prototype even posted it was silver and apologized for the picture is had to do with overexposure of the image.

2. The new vents and larger heat sink are not for a new cpu. They are simply there to make the new machine much quieter in normal use. People you've all been complaining about how loud the Quicksilver is and now that Apple has addressed the problem you can't even recognise it all you say is how ugly it is. This machine is designed to move much more air without making any noise in normal use. Yes when the VARIABLE FAN spins up to full speed it does make a quite a bit of noise but not really any more then the Quicksilvers.



Apple has provided us with a completely new machine whether you like it or not. It is not a lot faster for normal tasks but when you start editing large data files like video etc. it should be significantly faster. Also this computer has added a lot of functionality not only is it quieter but it also has an ATA 100 bus and an ATA 66 bus for support of 4 high speed drives without needing to fill anymore PCI slots.

I repeat this is a great leap forward for the proffesionals for who it is made for. So if you can't see this quit whinning and get an iMac or that friggin PC you keep talking about. Just remember that PC does not run OSX.
 
Re: Re: Re: Question

Originally posted by MacBandit
2. The new vents and larger heat sink are not for a new cpu. They are simply there to make the new machine much quieter in normal use. People you've all been complaining about how loud the Quicksilver is and now that Apple has addressed the problem you can't even recognise it all you say is how ugly it is. This machine is designed to move much more air without making any noise in normal use. Yes when the VARIABLE FAN spins up to full speed it does make a quite a bit of noise but not really any more then the Quicksilvers.
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Actually, everyone I've heard who has used the new machines so far says that they're even louder than the Quicksilvers. "Very loud" as some put it. That surprised me, because I too thought the new machine would be quieter.

Alex
 
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