I come back from a weekend-long vacation to discover my Mac Pro1,1 isn't displaying video from my EVGA GTX 650. I'm using DVI and my monitor states it as inactive, I've tried using VGA with the same results. I put the stock card in and it works fine. I've zapped the PRAM, reset the SMC, and disabled the Nvidia web driver in favor of the default one. Any suggestions? It booted and displayed once, but I think I am screwed. Calling support tomorrow.