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Test Settings

PCI Express & CrossFire: Scaling Explored
By

Test Configuration
Component Base Settings
CPU Intel Core 2 Duo E8600, (3.33GHz, 6.0 MB Cache)
Overclocked to 4.00 GHz, FSB-1600
Memory 2 x 2.0 GB Crucial Ballistix PC2-6400
Set to 800MHz data rate, CAS 4-4-4-10
Graphics 2 x Gigabyte GV-R487-512H-B
HD 4870 GPU (750 MHz), GDDR5-3600
Hard Drive Western Digital WD5000AAKS, 500 GB
7,200 RPM, SATA 3 Gb/s, 16 MB cache
Sound Integrated HD Audio
Network Integrated Gigabit Networking
Power Cooler Master RS850-EMBA (850W, ATX12V v2.2)
Software and Drivers
Operating System Windows Vista Ultimate SP1
Graphics Driver AMD Catalyst 8.9
Onboard Device Drivers Motherboard Driver DVD

While many of our test games show enormous performance gains from higher clock speed, none have shown significant improvements in the transition from two to four cores. Thus, we used a dual-core processor that usually overclocks beyond 4 GHz on air cooling. Intel’s Core 2 Duo E8600 is probably the best gaming processor owners of LGA775 motherboards can hope for their motherboards to support because it starts out as Intel’s highest-frequency model and is easily pushed beyond the speeds other processors can reliably run.

Overclocked to 4.0 GHz at FSB-1600, our Core 2 Duo E8600 required good RAM to achieve optimal throughput. Unfortunately, the oldest chipset in today’s line-up wasn’t designed to support DDR2-1066, and using the DDR2-1000 setting resulted in severe instability. Without the ability to increase memory speed, we instead settled for tight CAS 4 latencies at DDR2-800 and 2.00 volts. Crucial’s Ballistix DDR2-800 4.0 GB dual-channel kit worked perfectly.

With the support hardware in place, it was time to pick graphics cards. Though the targeted upgrade market of this piece will likely favor lower-cost HD 4850 or HD 4830 based graphics models, the HD 4870 allows us to test the limit of motherboard differences when using the same architecture as those two high-value solutions. A pair of Gigabyte’s GV-R487-512H-B graphics cards suited our testing needs well.

To further examine graphics performance differences, we added Race Driver GRID to our regular selection of benchmarks.

3D Game Benchmarks and Settings
Crysis Version: 1.2.1
Test 1: Low Details, No AA
Test 2: Very High Details, 8x AA
Demo: CPU-Benchmark + Tom’s Hardware Tool
Race Driver:
GRID
Version: 1.20.0000
Test 1: Low Details, No AA
Test 2: Very High Details, 8x AA
Track: Jarama
Supreme Commander
Forged Alliance
Version: 1.5.3599
Test 1: Low Details, No AA
Test 2: Very High Details, 8x AA
Demo: WallaceTX_006_006
Benchmark: Fraps 2.9.4 - Build 7037
Unreal Tournament 3 Version: 1.2
Sound and DirectX10
Texture Details: 1
Level Details: 1
Demo: vCTF-Reflection_fly
Time: 12/60
World in Conflict Version: 1.0.0.9
Test 1: Very Low details (No AA, No AF)
Test 2: Very High details (4x AA, 4x AF)
Demo: Game-Benchmark

Sythetic Benchmarks and Settings
3DMark Vantage Version: 1.02
GPU and CPU scores
SiSoftware Sandra XII SP2 Version 2008.5.14.24
CPU Test = CPU Arithmetic / Multimedia
Memory Test = Bandwidth Benchmark

Because different generations of chipset support different bus speeds, we also included Sandra’s CPU and memory bandwidth benchmarks to gauge the effects chipset overclocking had on performance.

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  • 2 Hide
    badge , December 8, 2008 7:16 AM
    Thanks for laying that information out.
  • 5 Hide
    sparky2010 , December 8, 2008 7:31 AM
    should've included 1920x resolutions in the last page, as there are a lot of people out there with screens capable of that resolution.. but anyways, all in all a very good and informative article.. but i'm going to settle with a complete makeover when core i7 becomes more available!
  • -1 Hide
    V3NOM , December 8, 2008 7:32 AM
    yer kinda interesting to see how things have changed with new mobos but it doesnt really have any practical value tbh.
  • 5 Hide
    Crashman , December 8, 2008 7:38 AM
    V3NOMyer kinda interesting to see how things have changed with new mobos but it doesnt really have any practical value tbh.


    It's all about answering the question "Will a second card do the job".

    Lots of guys have midrange or better ATI graphics cards, and the question of "upgrade or replace" is constantly being asked.
  • 0 Hide
    outlw6669 , December 8, 2008 7:50 AM
    Thanks for finally getting this review out!
  • 1 Hide
    arkadi , December 8, 2008 8:07 AM
    p45 looks grate, and the price is right.
  • -9 Hide
    arkadi , December 8, 2008 8:08 AM
    btw x58 is out there, just a reminder.
  • 1 Hide
    outlw6669 , December 8, 2008 8:20 AM
    @ arkadi
    Yes the x58 is out.
    However, as it can not be paired with a Core 2 CPU and runs DDR3 exclusively, you can not directly compare the results.
    In general, I would assume crossfire on the x58 will scale similarly to the x38/48 as they both have the same PCIe configuration.
  • 2 Hide
    Crashman , December 8, 2008 8:21 AM
    outlw6669Thanks for finally getting this review out!


    It was planned for September but kept getting delayed due to tight deadlines on other articles. But when the economy finally went from a slow decline to a nosedive in November, we knew this article had to come out right away. More people are putting new systems on hold and looking for ways to keep their old ones up to current performance standards, and we care about upgraders just as much as system builders.
  • -1 Hide
    arkadi , December 8, 2008 8:41 AM
    Yeah I know, the comment was in general...
  • 0 Hide
    dimaf1985 , December 8, 2008 9:51 AM
    great article. consise and informative at the same time. now if only there was one for amd chipsets...
  • 0 Hide
    marraco , December 8, 2008 11:39 AM
    Good work!.

    Altought, I have an Athlon X2 system, and probably gonna update to a I7 920. It would had be better comparing to an cheap i7 as a reference
  • 1 Hide
    Lurker87 , December 8, 2008 11:59 AM
    Excellent info. It'll be nice having this article to link to.
  • 5 Hide
    antiacid , December 8, 2008 12:34 PM
    This article shows that even in the best conditions, x48 vs p45 is at most 5% difference. Price-wise, this confirms my observations that the lower priced P45 boards are much better performance/value than the x48 premium counterparts.
  • 2 Hide
    Roland00 , December 8, 2008 12:44 PM
    I understand it is more testing, and you already had several months of delays but it would have been nice to see 1920x1200 numbers. 24" monitors are now in the mainstream affordability range with prices ranging from $249 to $349
  • 1 Hide
    waffle911 , December 8, 2008 12:54 PM
    I might be missing something, but it kinda looks like a Phenom 9950 paired with the 790FX SB750 would be comparable to the X48. But really, what am I missing? I can't find a direct comparison anywhere.
  • 0 Hide
    waffle911 , December 8, 2008 1:01 PM
    Sorry: bit of an oversight on my part. CPU charts of course, though the AMD board is using the older SB600, but the performance difference shouldn't be much different.
  • 2 Hide
    Crashman , December 8, 2008 1:03 PM
    Roland00I understand it is more testing, and you already had several months of delays but it would have been nice to see 1920x1200 numbers. 24" monitors are now in the mainstream affordability range with prices ranging from $249 to $349



    You're right! The problem is trying to test a whole bunch of different resolutions. 1920x1200 is almost right in the middle between 1680x1050 and 2560x1600, so hopefully most people can figure out "about" where that resolution would fall on the charts.

    Is it time to get rid of 1024x768? I'm in favor of ditching that resolution and picking a different one.
  • 0 Hide
    FlorinR , December 8, 2008 1:08 PM
    I'm trying to figure out something after reading this article, maybe someone could help me understand??? It seems that a SINGLE Radeon HD 4870 still have enough bandwidth into a PCI-E 1.1 slot, and the differences in performance compared to PCI-E 2.0 came from the chipset (P35 vs. P45 in SINGLE card configuration). Am i wrong?
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