Hi Folks, There's a lot of info out there on this (and other) forums about adding a GTX 780 to the Mac Pro 5,1 by using an external PSU but I wanted to post my own thread to see if anyone can quell my concerns before I take the leap. Please see below my system specs... If anything sticks out as unusual please feel free to comment. In the future I'll be switching to PC but I want my mac to run as long as possible and considering these are PC hardware I can re-suse them if need be. My question is, will the GTX 780 definitely work out of the box with 10.8.4 on a mac pro? Ive heard reports that it does but mainly from the Hackintosh community. Also, if I were going to keep my current 5870 and add the 780 can anyone advise me on the best PSU to use and how to go about telling my mac to power displays with 5870 and grunt with the 780? Any point doing that? One last thing, if I go with the external PSU I'll need to fathom out how to connect the two so power up controls both devices.... rather than having to turn both on and off separately. Is this mind boggling or easily achievable? MY SYSTEM: Mac Pro 5.1 (2010) OS X 10.8.4 2 x 2.93 GHz 6-Core Intel Xeon 32 GB 1333 MHz DDR3 ATI Radeon HD 5870 1024 MB 3 TB RAID (3x1TB) 240GB OWC Mercury Accelsior OCIe SSD (Running OSX) 240GB OCZ SSD (Running Windows Bootcamp) This is primarily for After Effects but gaming on the PC side... Im a whore for FPS so the 5870 just doesn't cut it anymore. Thanks for any advise!