I recently noticed I have PhysX installed on my new build, but my GPU is a Sapphire Vapor-X Radeon HD 7770 GHz Edition/Overclock Edition. I figured since I don't have an nVidia GPU I couldn't even install PhysX. Is there any way to know if it's actually working?
Phys-x can be used with your CPU. So that is why you have it installed, nvidia cards can just utilize phys-x more efficiently than your CPU. So yes it does work (my reference would be how I run Phys-x on borderlands 2). I hope i helped you out,
Phys-X was originally a CPU thing, then Nvidia optimized it to offload Physics calculations from the CPU onto the GPU while also providing dynamic physics/movement capability, Physx is installed because of your CPU.