Hey, I am soon to own a 7970 and an FX8350 and was wondering about PhysX and was wondering about how much of a hit it would take. It would really only be Planetside 2 and Witcher 3 that i would play supported with PhysX although there could be more....
Second question and most important xD I would like another opinion on the psu I need, i was told a 750-850 will do if its good enough but would like more clarification as I have seen an AX750 with braided cables for £110.
System Spec:
FX8350 with H100i (push or pull and OC @ 5Ghz hopefully)
As for your first question, you are able to use your CPU for Phys-X in games, though granted it will not be as good as nVidia GPUs made for Phys-X but you can get the driver for off their website and find a tutorial on how to do it off Google/Youtube. It should't really be that big of an issue but that is a definite solution if you are worried about Phys-X performance with and AMD GPU. Good luck!
You can run PhysX off the CPU, so you aren't limited to a Nvidia card, and you'll be running a 8-core. And you should be fine with a Corsair AX750. Its an awesome PSU, and I had one in my last rig, which was running 2 6970's, and I had no problems.