3DMark06
I've included scores for the Radeon X1900 XTX CrossFire rig below, despite the fact that we saw big problems with visual artifacts in graphics tests three and four of 3DMark06. The CrossFire system's performance also didn't scale as well as expected from one card to two, and I suspect the visual artifacts played a part in that. I was able to confirm that the problem wasn't confined to the Radeon X1950 CrossFire setup by trying a Radeon X1900 CrossFire rig, which exhibited the same problems. I suspect some sort of driver problem or a mild incompatibility with our Intel D975XBX motherboard. We're working with ATI to find a resolution, and we'll update the scores here once we have one.

Update: We were able to overcome the CrossFire issue by switching to an Asus P5W DH motherboard. On that board, the Radeon X1950 CrossFire system executed 3DMark06 tests three and four without any problems, and the overall 3DMark score is higher as a result. The updated graphs are now in the article below.

The Radeon X1950 XTX's extra memory bandwidth allows it to open up a slim but decisive lead over the GeForce 7900 GTX here. At the same time, the Radeon X1900 XT 256MB demonstrates that it has the GeForce 7900 GT outclassed.

3DMark's quick vertex and pixel shader tests don't reveal much new to us, but we've included them for the sake of completeness.