Hello all, I am trying to get a GTX 580 to work on my Early 2009 Mac Pro. From the posts around here, it appears that PC graphics card should be able to work in Boot Camp, but I have a black screen all the way when booting into Windows (even after hearing the Windows login sound). So now I'm baffled. Is my power supply not enough? I am using the two 6-pin PCIe cable in the Mac Pro (one is plugged into the 580's 8-pin). Can anyone offer some input on this?