Gaming performance - DOOM 3
Here's the same testing with DOOM 3. Note how the SLI'd 6800 Ultras are starved of CPU grunt until at least 1600x1200. Again, the performance advantage of equivalent S939 CPUs is manifested in higher average framerates at the lower resolutions, and higher at all settings with SLI.
There's very little single-card difference with AA and AF applied. Some still exists with SLI'd Ultras, though.