I ran the game benchmarks at 1024x768 and 1280x1024 with 32bit color. My monitor could not support 1600x1200 so I wasn't able to benchmark at that resolution. I used Benchemall to benchmark the following games.

Half Life 2:
Half Life 2 is very dependent on the CPU, so I didn't get that great of an improvement with SLI vs. without.

Doom 3 Now Doom3 is very video card intensive, you can see a pretty good difference between SLI and without.

There is a 57% improvement at 1024x768 with SLI, and a 32% improvement at 1280x1024.

Far Cry With Far cry I actually got lower scores using SLI then I did when I wasn't using it. I think that is because of the CPU I used.