I have a 8800GTS 640mb under RMA, am hoping to get a GTX 260 as a replacement (fingers crossed!) .. if that happens I'll mostly sell off my 4870 and get a second 260 for SLI. I have a 600W FSP Epsilon 80+ psu (OCZ's & OEM supplier) it looks like a quad rail 18a psu. Will this be enough or should I upgrade this also incase I go ahead with sli or crossfire? Specs in my sig.