"BARE facts on Mac speed FEATS"
Rob-ART, Main Mad Scientist (aka Dr. Frankenstein)
Bet-TAY, Special Features Edtior (aka Frau Blucher)

MEMORY COMPARED:
800MHz versus 667MHz FB-DIMMs
in Mac Pro 3.2GHz 'Harpertown'

Originally posted January 22nd, 2008, by rob-ART morgan, mad scientist
Updated January 28th, 2008, with STREAM 64-bit MP results

Some of you have a big investment in 667MHz FB-DIMMs from the 2006/2007 Mac Pro. You're wondering if you can transfer it to the 2008 Mac Pro instead of buying 800MHz FB-DIMMs as specified -- if only temporarily -- without taking a big performance hit. We have an answer.

TABLE of TEST RESULTS
This is what we learned when we put eight 2GB 667MHz FB-DIMMs in our 3.2GHz 8-core Mac Pro "Harpertown":

FB-DIMMs (CAS 5-5-5) compared	667MHz	800MHz	Advantage
Xbench Fill Rate MB/s	12081	12556	3.9%
Xbench Copy Rate MB/s	6348	6468	1.9%
GeekBench Memory Rating	2944	3069	4.2%
Geekbench Stream Rating	2020	2082	3.9%
Cinbench 10 CPU Render Rating	21043	21354	4.2%
Photoshop CS3 Actions 300MB	88 sec	88 sec	0%
After Effects CS3 TotalBenchmark	127 sec	127 sec	0%
Aperture Lift and Drop Adjustments	31 sec	31 sec	0%

STREAM 64-bit RESULTS
John Poole at Primate Labs (creators of Geekbench) made a special 64-bit and parallel multi-threaded (openmp) version of STREAM 5.8 for us. Look what happens when you put 667MHz memory in a "2008" Mac Pro 'Harpertown.' Surprisingly, the 800Mhz memory is only 2% faster based on this test.

ANALYSIS
If you have a big investment in 667MHz memory, you can use those FB-DIMMs with the new Mac Pro. The tests we ran show a maximum penalty of 4% in speed. Considering the advantage over the 3.0GHz 8-core "Cloverfield" Mac Pro ranges from 18% to 24% when running Photoshop, After Effects, and Aperture, you might feel you can live with a 4% hit.

But if you want to squeeze every ounce of speed out of your new Mac Pro, then you'll want 800MHz FB-DIMMs -- eight sticks preferred.

FUTURE PROOFING
If you own a 2006/2007 Mac Pro that takes 667MHz FB-DIMMs and you are planning a memory purchase, you might consider buying 800MHz FB-DIMMs. They work fine, though they will run at 667MHz. Yet if you are planning to buy a 2008 Mac Pro in the near future, going with 800MHz FB-DIMMs will "future proof" your memory investment.

RELATED LINKS

Bare Feats' CPU crunch tests on the 3.2GHz Harpertown Mac Pro versus others.

Bare Feats compares the Radeon HD 2600 XT to the optional GeForce 8800 GT.

Bare Feats tests 12 different configuations of 800MHz memory on the 3.2GHz Harpertown Mac Pro.

Bare Feats' power usage and noise level testing on the 3.2GHz Harpertown Mac Pro vs the 3.0GHz Clovertown Mac Pro.

WHERE TO BUY A MAC PRO
When ordering products from Apple Store USA, please click THIS TEXT LINK or any Apple display ad as your "portal" to the online store. In so doing, you help to support Bare Feats.

Also check with Small Dog Electronics and Power Max. (Power Max takes trade-ins.)

NEED 667MHz or 800MHz memory for your new Mac Pro? Apple's memory is too pricey for my blood. I suggest ordering your new Mac Pro with minimal memory then ordering four or eight matched FB-DIMMs from one of the following:

Other World Computing

Trans International

MaxUpgrades makes max_flow, a kit to keep your Mac Pro memory running even cooler. They also have a kit called "MaxConnect" which enables you to use the lower optical bay to add four more internal hard drives for a total of eight.

Has Bare Feats helped you? How about helping Bare Feats?

© 2008 Rob Art Morgan
"BARE facts on Macintosh speed FEATS"
Email , the webmaster