We already saw this phenomenon in Windows XP and crossing over to Windows Vista or using Catalyst 8.3 changes nothing. AMD hasn't profiled Test Drive Unlimited to work in multi-GPU configurations. NVIDIA has done so. The result is a very large gap, with the 3870 X2 being two times slower on average than a simple 8800 Ultra. On the other hand, the 9800 GX2 widens the gap. There's a nuance here. It varies between 26% and 67% at 1920x1200, but the 512 MB limit reduces the gap to 33% and 18% at 2560x1600. This card, like the 8800 Ultra, can't run the game smoothly when antialiasing is on; 28 frames per second is too low for Test Drive Unlimited.