Just got the pc version of the gtx 680. Works great. Huge bump to fps in wow under OS X and bf3 under windows comparing to 5870 Now, I want to flush it Mac rom. Ill follow this post http://forums.macrumors.com/showthread.php?t=1565735&page=6 but the only card I have that wont need a power cable is gt120. Will this work, or do I need an ati card so that i dont screw up the gt120?