SLI needed for Dedicated Physx?

Hi  

I'll say it first, I am somewhat of an Nvidia newb. To start off with, I bought a Crosshair IV which is Crossfire only, not SLI, but has 3 graphics card slots. And I got a Gtx 480. Out of curiousity for the future, is an SLI ready motherboard needed to set up a dedicated Physx card or can it be done with any motherboard that has 2+ 16x or 8x PCI-e slots? I have a 9600 lying around in my old computer. I know it won't give me much of a performance boost at all, but I do usually notice it sometimes, mainly considering I watch my FPS ingame with codes or Xfire   and any FPS boost at all makes my day.