The site claims this driver will offer a significant boost for GeForce cards in 3DMark Vantage, the performance of a GeForce 9800 GTX in Vantage goes up from P7000 3DMarks to P8000 3DMarks due to the much higher CPU score and the site also claims the PhysX driver boosts the performance in the PhysX enabled version of Unreal Tournament 3 from 30FPS to 70FPS.
The Tech Report has a bit more on this:
As if the plot weren't thick enough, Nvidia has preliminary PhysX drivers for the GeForce 9800 GTX, 9800 GTX+, and GT260/280 cards, which it says provides a nice boost in 3DMark Vantage scores—in part because, surely controversially, scores in one of 3DMark's so-called "CPU" tests will benefit from GPU PhysX acceleration.