I heard that you cannot have a dedicated physx card when you use an AMD card as your primary graphics processor. I plan on buying an R9 290 on cyber monday and I'm not sure if I will just loose physx all together. Assuming that my 850W power supply can support it, I was planning on using the 290 for graphics, and my old(ish) 670 for physx. I would sell my 670 but I don't know anyone who wants to buy it off of me and I don't truse Ebay/Craigslist (otherwise I'd sell it and use something like a 650 for physx).