Though still in beta status, NVIDIA have made available their latest ForceWare 169.09 drivers today; these are particularly Crysis happy as they add full SLI support to the game, fix a major water reflection bug and also add Control Panel anisotropic filtering support.
Running Crysis in SLI should now yield a 40 to 50% increase in overall performance, and an upcoming patch from Crysis is said to push SLI performance even further again.
NVIDIA have kindly provided some reference performance numbers in Crysis by using the built-in benchmark with these new drivers:
Setting Single SLI Scaling
GeForce 8800 GT 512MB
1600x1200 High 24.05 34.76 45%
GeForce 8800 GTX 768MB
1920x1200 High 22.7 31.87 40%
Grab the new drivers here folks.