You seem to think that you need to have SLI or Crossfire for a physX card. They have nothing to do with each other. I have a GTX 680 as my normal video card and a GTX 480 (old card) for Physx. There is NO SLI connector between the 2 or anything like that. The video card driver just sees the second card and I can select which one I want to use for Physx or let it auto set it.