Tesselator started a relevant thread here regarding the GTX 570 in a MacPro1,1 system: http://forums.macrumors.com/showthread.php?t=1583383 So I guess we know that the GTX 570 will run in a MacPro1,1. My question is what are the requirements to run a GTX 570 in a MacPro2,1? OS X Lion minimum? Additional power required? Any workarounds needed, or Lion drivers should support the card? What about OpenCL, OpenGL support? Anything else I'm missing? Also, Macvidcards offers the GTX 570/580 but states MacPro3,1 or higher is required. If Lion can be installed on a MacPro1,1 system, why would a MacPro3,1 system be the minimum requirement? http://www.ebay.com/itm/Nvidia-GTX-...114?pt=PCC_Video_TV_Cards&hash=item35c6aea1b2 Thanks!