I can run the game on Ultra as long as I keep PhysX turned off on my build, if I turn it on it runs great for like 10 mins then all of a sudden my frame-rates flux from 1-130 really really fast right before getting a CTD. I am running the most up to date drivers for my 580, and I'm running a Bloomfield 960 i7 processor clocked in at 4.2 ghz stock OC to 4.8.
have you updated the physx drivers? You can do that additionally to the actual gpu drivers... may not help though, implementation in PS2 isn't the best.
Nvidia experience keeps all that up to date for me, I also checked to make sure that I had the most up to date drivers and I do.
320.18 screwed up PhysX in PS2 for me, on my 660Ti, so you might want to go back to 314.22. It seems to be the best in terms of stability.
