Leave it to the public to circumvent the restrictions put on by companies. Windows 7 lets you use different graphics card and up until recently you could have stuck in an ATI graphics card for graphics rendering and a NVIDIA card for PhysX.
Well, NVIDIA
put a stop to that with a recent driver update but someone's gone and put out a
patch to re-enable it. It's an unsupported solution of course and who knows what it will do to your system other than re-enable the feature. Either way, if you're one of those folks you can try it out if you want those cool little PhysX features back.