Put a GTX260 next to my HD5870 and the results from Fluidmark are following:

Physx OFF: FPS: min=7 max=325 avg=25

Physx ON: FPS: min=117 max=431 avg=152


My CPU is an E8400 OCed to 4.0ghz. The GTX260 was at stock clocks during the tests.

If anyone has problems getting physx to work, follow this guide: http://www.mymobile88.com/enable-act...ation-guide-2/