ATI MultiGPU Done Right: The Radeon X1800 CrossFire Edition
by Derek Wilson on December 20, 2005 9:00 AM EST- Posted in
- GPUs
Day of Defeat Performance
Day of Defeat: Source seems to be hugely CPU limited with this kind of GPU power pumping through the game. This is especially true when running without antialiasing. Both of our tests have 8x anisotropic filtering enabled, but that doesn't seem to make a dent in any of our multiGPU configurations. We can see that CPU limited cases, SLI seems to incurr a little more CPU overhead. Thus the single card 7800 GTX 512 score is better than it's SLI performance.
Under the antialiasing tests, there is a much more severe drop in performance after 1600x1200. All but the dual 512MB part configurations fell to under 50 FPS at 1920x1440. Under the highest stress conditions, the 7800 GTX 512 SLI manages to barely outperform the X1800 XT CrossFire, but the rest of data points to what we've seen many times before: ATI hardware performs very well under Valve's Source engine.
Day of Defeat: Source seems to be hugely CPU limited with this kind of GPU power pumping through the game. This is especially true when running without antialiasing. Both of our tests have 8x anisotropic filtering enabled, but that doesn't seem to make a dent in any of our multiGPU configurations. We can see that CPU limited cases, SLI seems to incurr a little more CPU overhead. Thus the single card 7800 GTX 512 score is better than it's SLI performance.
Under the antialiasing tests, there is a much more severe drop in performance after 1600x1200. All but the dual 512MB part configurations fell to under 50 FPS at 1920x1440. Under the highest stress conditions, the 7800 GTX 512 SLI manages to barely outperform the X1800 XT CrossFire, but the rest of data points to what we've seen many times before: ATI hardware performs very well under Valve's Source engine.
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almvtb - Tuesday, December 20, 2005 - link
Has anyone ever compared SLI and crossfire performance using a dual core compared to just a single core cpu? I mean if there is enough overhead for sli or crossfire a dual core chip could improve performance.kristof007 - Tuesday, December 20, 2005 - link
I don't know if that dual core thing would work. I mean it might but the two slower CPUs would not help in my opinion. Games are single threaded so the multi CPU wouldn't take off the overhead .. at least that's my knowledge of it.almvtb - Tuesday, December 20, 2005 - link
See I thought that was a big deal with one of the latest Nvidia driver releases. That it was made multithreaded so that in a situation such as when you have sli or any other kind of driver overhead it would be taken care of by the a second core if one existed. I do not know it was just a thought that i had never seen discussed, so I thought I would ask.bob661 - Tuesday, December 20, 2005 - link
That was an ATI driver release that had the multithreading stuff, I think.kilkennycat - Tuesday, December 20, 2005 - link
We shall shortly soon find out whether Crossfire is serious or just a ATi marketing straw-grabbing ploy to get some suckers (er, "enthusiasts") not to buy SLI. If the compositor is fully integrated into EVERY R580 GPU, (thus never requiring a masterboard and implementing the board communications via a passive bridge a la nVidia) then we shall finally know that ATI is serious with Crossfire. It was probably a stupid cheese-pairing management decision not to integrate the Crossfire functionality fully into the R520 GPU, or else Crossfire does not have enthusiastic support from ATI engineering and is purely a ATi marketing ploy anyway. The R580 details will reveal the truth.Spacecomber - Tuesday, December 20, 2005 - link
What changed since the http://www.anandtech.com/video/showdoc.aspx?i=2466...">Battlefield 2 GPU Performance Analysis article? It seemed like you were able to demonstrate the advantages of SLI in those benchmarks.Space
bob661 - Tuesday, December 20, 2005 - link
I think AT has a different benchmark now for BF2.Spacecomber - Thursday, December 22, 2005 - link
As far as I know the only thing that has changed along the way are the addition of BF2 patches (according to the overclocking the Athlon X2 article, they are up to using the 1.03 patch) and newer nvidia drivers. I believe they are still creating a demo and running it with the timedemo option. With this being such a popular game (BF2), it seems like it would be worthwhile to confirm whether SLI/Crossfire does or does not offer significant improvements for BF2.ViRGE - Wednesday, December 21, 2005 - link
Ya, DICE seems to screw up demos with new BF2 patches.ElFenix - Tuesday, December 20, 2005 - link
i wonder if you can change b&w2's name to make the score go up as well. maybe there is poor optimization going on in the catalyst AI?