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Originally
posted 9/21/02 by rob-ART morgan, mad scientist 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
3
FOR Filemaker, Bryce, Cinema 4D, and
Multi-Tasking
results) CONCLUSION 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. RELATED
LINKS 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 TransIntl.com. TEST
NOTES The "SDR" Power
Mac 1GHz MP had 1GB of PC133 CL2 SDRAM. All three were
running from an IBM 120GXP drive. For details on
each real world test, read "HOW
I TEST."
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HOME PAGE SPEED TEST RESULTS by Category LINKS to SPEED tests on other sites HOT DEALS on speed upgrades rob-ART
morgan,
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Morgan "BARE facts on Macintosh speed FEATS" Email webmaster at rob-art@barefeats.com
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