NVIDIA is working hard on a new driver that should improve performance and add SLI support for the new S.T.A.L.K.E.R. game.
One thing we've already noticed in our S.T.A.L.K.E.R. testing is that the GeForce 8800 GTX doesn't perform that much faster than the GeForce 8800 GTS 320MB with today's 97.92 driver, so hopefully the upcoming driver will really allow the GeForce 8800 GTX to flex its muscles.
The new ForceWare driver is expected to arrive next week.