BARE facts on Macintosh speed FEATS


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Power Mac 1.25GHz MP versus others

Originally posted 9/21/02 by rob-ART morgan, mad scientist
Updated 9/26/02 with added results from Bare Feats' CompUSA "lab."
Mahalo to remote mad scientist, Mike, for his initial results.


In my comparison of the DDR 1GHz Power Mac to the SDR 1GHz Power Mac, I wondered "out loud" if the 1.25GHz version would utilize the DDR memory in a more effective way. In other words, will the speed difference be more than the 25% increase in clock speed?








(SEE PAGE 2 FOR Quake3 Arena and Unreal Tournament RESULTS)

(SEE PAGE 3 FOR Filemaker, Bryce, Cinema 4D, and Multi-Tasking results)




The advantage of the 1.25GHz MP DDR Power Mac varies, depending on the application. In 8 tests where CPU crunching was dominant, I saw a 23 to 42% gain over the 1.0GHz MP DDR Power Mac (or average gain of 28%). So it's safe to say that you can expect performance in keeping with difference in clock speed.

It's important to note that compared to the old SDR Power Mac, there is still no advantage to having DDR memory. The average advantage over the 1.0GHz SDR Power Mac was 27%. So those who suggested that the size of L3 cache was a factor are wrong. The speed advantage of the 1.25GHz model has more to do with faster CPU's than faster memory bus, faster system bus, or size of L3 cache.

The exception to my contention was when I did a Gigabit network transfer while rendering a Cinema 4D logo. The 1.0GHz DDR model showed a 22% advantage over the 1.0GHz SDR model. And a 19% advantage when running Quake3 while doing the transfer. (The 1.25GHz DDR model was even more dramatic with 76% and 35% advantage respectively.)

As for the "bang for the buck" factor, it depends on how you configure the system. In my "what if" exercise, I created a "build to order" 1.0GHz DDR Power Mac to match the standard config of the 1.25GHz DDR Power Mac. The "1.25" cost 18% more. Compared to the 1.0GHz SDR "closeout" system, it was 57% more. But then, those are getting scarce.

If I needed a G4 tower today, I'd buy the 1.25GHz model. But since I have a 1.0GHz SDR Power Mac already, I'm sticking with it until I see what Apple does in 2003. I consider the current Power Mac line "stop gap" editions until the true "wintel killer" can be engineered.



MacWorld has results for the 1.25GHz MP DDR Power Mac. If you average their results from Photoshop, iMovie, iTunes, Cinema 4D, and After Effects, it's 21.3% faster than the 1.0GHz MP DDR Power Mac.

Apple has published some test results of their own using Photoshop, Final Cut Pro, and DVD encloding (iDVD?). You can download the Technical Overview PDF with these results. They haven't responded yet to my request for details as to how these tests were run so we can't duplicate or verify the results.

PowerLogix published an in-depth white paper discussion (PDF ) comparing single data rate static RAM ("SDR") architecture versus double data rate ("DDR") when designing the level 3 cache circuitry for use with the latest Motorola G4/745x processors.

If you buy a new DDR Power Mac, make sure you specify DDR PC2700 333MHz (Non ECC) 64x64 CL2.5 memory. Check with OWC and



The "SDR" Power Mac 1GHz MP had 1GB of PC133 CL2 SDRAM.
The "DDR" Power Mac 1GHz MP had 1.25GB of PC2700 CL2.5 DDR RAM
The "DDR" Power Mac 1.25GHz MP had 1.5GB of PC2700 CL2.5 DDR RAM

All three were running from an IBM 120GXP drive.

For details on each real world test, read "HOW I TEST."




LINKS to SPEED tests on other sites

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rob-ART morgan,
mad scientist and webmaster


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