Will an AX 860 be enough to power a 4770k along with a gtx780 Ti in sli with gtx750
you can't SLI GTX 780 ti with a GTX 750 ._.
Nvidia GPU's need to be of the same chip to SLI, While you can run a GTX 780 ti and GTX 750 in one machine, Only one of the GPU's will do the rendering while the other GPU can be used for the odd game with Crossfire.
Crossfire is AMD.
i'll assume he meant physx