As you can see, the game is highly CPU-bound: cranking up the screen res hardly shows any performance difference even at 2560x1600! As a result, obviously performance between the GTX and Ultra cards isn’t all that different, even including the SLI setups; the GeForce 8800 GTS 320MB does lag behind the other cards though. The GeForce 8800 GTS 320MB runs at the same speeds as the 640MB board, but runs 9% slower at 1600x1200. This margin eventually increases substantially at 2560x1600.
If you’re wondering where the GeForce 8800 GTS 320MB SLI numbers are, we decided to exclude them because we ran into visual corruption problems and the scaling was really poor.