Just tried running FurMark tonight on my 2009->2010 Mac Pro with an eVGA GeForce GTX 780 modified by MacVidCards, which to my knowledge was a stock-clocked board. Within a second of running FurMark, the system blinked off. I've had no problems running any games, Luxmark, or Heaven, but FurMark caused an instant shutdown. I've had no other power-related issues with this system. Looks like I'm going to need an FSP Booster PSU. Evidently, not all 2009+ Mac Pros will be able to run a 780 without running into power issues. Since MVC has questioned the veracity of my concern, I'd request that anyone who's purchased a 780 from MVC who's got Windows run FurMark's 60 second benchmark and please post your results here. I'd like to see how many others experience the same issue. 10/31 Update - FurMark does NOT power off in OS X, but does under Windows, for me - Curious to see if anyone else has this happen under Windows specifically Note - I've got no problems playing games, running AE, Unigine Heaven, etc., but FurMark shouldn't blink the system off in a second or two.