Its an graphics option that yes, is available for nvidia cards. But It is merely an eye candy if you'll ask me. check videos from youtube for the differences of having it and not. And also, not all games have it, only few. try to google the games that have it, The only popular ones I can think of is, batman arkham city, borderlands 2, metro 2033. But there are still more, just check if you'll be playing them and if you can paly without physx. But for me, I would still prefer a 7950 over a 660 ti if your not that affected without physx.