Here is our current test system.

Our test OS was Windows Vista Ultimate SP1 with Nvidia's 175.12 of Forceware drivers and ATI Catalyst 8.4. All the latest software revisions were used in our testing.

As far as single GPU solutions go the Asus 9800 GTX leads the pack at 26.3fps at 1920x1200 in Crysis on high with DX10. In SLI this this bumps up to 34.3 fps.

Unreal Tournament 3 gives some excellent results for the 9800 GTX besting two 9600 GT cards until one gets to 2560x1600 resolution.

Quake Wars is one of the last Open GL games on the market and as always with Open GL games it favors Nvidia heavily. SLI combination of 9800 GTX is definitely unbeatable in Quake Wars.

Episode 2 isn't very demanding at even HD resolutions so we only tested at 2560x1600. 9800 GTX again comes out on top and hits 81.6FPS in SLI.

3DMark is a synthetic benchmark but very popular to see hardware potential. Things are more even across the board here.

Overclocking we were able to get a nice boost to 710MHz for the core and 1.25GHz for the memory which yielded about an extra 5%.