The GTS 450 apparently does pretty well for PhysX
Yeah, Lunawolfy, the video you posted has a 8600GT as the dedi Physx card

I think the GTS 450 is faster than the 9800GTX and the 9800GTX destroys the 8600GTS. So your comparison and point isn't really accurate. If you know differently could you post something of relevance please as I'm pretty interested in this.
