I can play almost all games at max (resolution 1600 x 900). But yesterday i started playing mafia 2, but after playing for about 60-75 mins when i entered into gunfire combat scene, fps rate went down drastically. like from 40 fps to almost 5 fps.
I have set physx eneble @ high.
Does this have any concern with allhigh settings or just phyxs.
Based on your sig you have a amd card which does not support physx.so physx is running on your cpu which cannot make those calculations so just turn of physx and play the game or buy a dedicated nvidia graphic card just for physx
physx is your problem. turn it off or set it to low. If you want it on high you need a dedicated physx card which needs to be Nvidia. Nvidia has restricted physx so it can only be processed on their cards or a CPU. Processing on CPU is extremely slow (which is what is happening to you). You wont notice much visual diff by turning it off, just a bit less smoke and less particle effects. better than having 5 fps.