Performance and Thoughts
DFI had an Athlon 64 4000+ Clawhammer powering the Crossfire system, so I built an equivalent Clawhammer FX-55 based system, clocked it down to FX-53/4000+ levels at the same 2-2-2-6 memory timings that they had, and benchmarked 3DMark05 at the same settings that PD used to test the Crossfire system while he was up with DFI during Computex. I used a DFI LanPartyUT nF4 mainboard for my testing, NVIDIA's 77.62 driver and ATI's CATALYST 5.6 for the graphics boards (6800 Ultras and 7800 GTXs, and a lone Radeon X850 XT). The driver used for the Crossfire system corresponds, I think, to a CATALYST 5.7 Beta code drop.3DMark05 - Default Settings - 1024x768 NoAA NoAF
Notice the multi-VPU mode, running AFR, is faster than the Supertiling mode the 'full' Crossfire system is running. 6800 Ultra SLI (using AFR mode) comes out slightly quicker than X850 XT Crossfire (Supertiling) with 7800 GTX SLI on top, although not by much due to CPU limitations. Crossfire Supertiling is around 60% faster than a lone X850 XT in the comparison system.
3DMark05 - 1280x1024 4xAA 16xAF
Turning up the resolution and IQ enhancing features has 6800 Ultra SLI ahead of the X850 XT Crossfire system in Supertiling and AFR modes. Note however that the Crossfire system was running the maximum of 6x anti-aliasing as selectable in 3DMark05's options panel. The AFR-driven slave-slave is nearly twice as fast as Crossfire Supertiling. Neither Crossfire setup is enough to catch up with the single 7800 GTX in that test configuration. In SLI mode, 7800 GTX will give nearly 10000 marks with an FX-53 and the current driver.
Thoughts
Using Supertiling, the default mode for Crossfire under Direct3D, shows that 6800 Ultra SLI is faster. However that's just in 3DMark05, not a modern game title, and that's using a beta driver that might not be there in terms of the performance that ATI have today, internally. It'll be interesting to see where performance is when Crossfire is launched using an official driver, along with NVIDIA hardware running any new driver that NVIDIA may or may not have planned for their hardware.We'll bring you a full evaluation of Crossfire (and I sorely need to update my original technology preview with fixes and new infomation!) as soon as it launches. Hope you enjoyed the peek we had at Computex.
