Windows 7: batman arkham prison demo: slow/jittery play

hi, i've got an amd 2 x4 940 with a GeForce 8600GTS video card running windows 7 64 bit. Batman Arkham demo installed fine but, as soon as the intro video is down, the play is very jittery, slow. I checked and installed th latest nVidia 8600 driver but no change.

Any ideas ?

Your graphics card is not a very good one. Thats the problem here. Buy a new one, or try to lower all the graphics to their lowest.

I don't think that's the problem: for grins, i installed the same demo on an older vista machine i have with a nVidia 7600 GT and it plays *much* better. When i say it's jittery, i mean, it's unplayable: the frame rate seems to be 1 / second

just courious do you have physx turned on??
i know in the retail if you try to run it with it turned on with a non suppoted physx card it slows the game to a crawl
if you have it turned on try turning it off

Good call: turned off Physx and it became very playable. Looks like i have two nVidia cards that can't do physics: i may be purchasing a new card a newegg

Do that, and rep that other guy that helped you!