Should I have PhysX processed by my graphics card or CPU?

[Fuzzball]

I have a fairly decent gaming laptop with an Intel Wuad Core i7-3630QM @ 2.4GHz, 8GB RAM and GeForce GTX 675MX. I've noticed in my NVIDIA Control Panel there is an option to choose my "PhysX processor", either auto-select, the GPU or CPU. I think at the moment (because I had forgotten to change it after installing drivers) it has been on auto-select.

Is there a general rule as to whether I should let the CPU or GPU process PhysX? I noticed earlier today (when it was auto-selecting the PhysX processor) that a scene in Mirror's Edge where guards where shooting through glass at me absolutely tanked the game's frame rate. When I turned of PhysX in-game things became fine and smooth.

Could I still leave PhysX on if I force it to use the "right" hardware to process it? Or is it something that has too much of an impact on performance anyway?

[Fuzzball]

Originally posted by Fred:

It depends whether your central processing unit or graphics processing unit is stronger. Leaving it to auto pick would probably be the best choice.

Fair enough. It's just I think we've all noticed computers can sometimes make some pretty dumb choices when left to choose things for themselves.

Anyway, I played that Mirror's Edge scene again, trying it with the GPU processing PhysX then the CPU. Both times the framerate tanked, so I guess it's just my hardware can't handle the PhysX in some parts of that game. Odd, as it handles the Arkham games fine.

[Ank]

GPU PhysX should be stronger than the CPU one since the CPU graphics is Intel based one like Intel HD graphic that is integrated with the processor. So basically you have dual VGA card, one is integrated with the processor, one is dedicated. You may use the CPU/integrated graphic for daily work but for gaming or video processing, using the GPU one is recommended. Yet, I notice you use the i7 3630QM 2.4GHz processor, I use the exactly same processor yet I don't have the integrated graphic card, so I don't have the option to choose CPU graphic option.

[Fuzzball]

Ah right, so even though it says using CPU is an option, it actually means just just using the integrated graphics card. Don't want to use that thing when running games!