I am considering buying a EVGA GTX570/Superclocked card. I was wondering if this card will work without an additional PS. Does the overclocking of the processor 1.work in the mac pro,2. are there any additional heat or power issues to consider. IE does the overclocking demand more power than the regular version? I know I could send it back if it did not work... I am getting the 1280mb version to leave behind the "above 2gb issue". Also many of the EVGA cards have a rebate of $20 on Amazon through October. It might be the time to move on a new card for others too. If you already bought one you have 30 days to claim the rebate. I am running a 2009 4,1 version of the Mac Pro with 1 Quad core 3.33mhz processor with 12Mb on board memory and the GT 120 video card.