I purchased a GTX760 to use in my Mac Pro. I have a 7970 that I was going to use in a small form factor build, but it was a tad too long. The GTX760 fit perfectly, so I decided to see if the 7970 would work with the Mac Pro and do a little testing to see if it would be fine for the long haul. I plugged the card in using two PCI extenders I found on eBay and used a 6-pin to 8-pin adapter that came with the GTX760. I know the TDP of a standard 7970 is 250W, just over the 225W limitation of the 2x6Pin connectors. The 7970 isn't nearly as power hungry as a GTX580, so I'm not too worried about it especially since I hardly use it "maxed out." I fired the Mac Pro up and waited through the black screen. I got to the login screen in about 10-15s without issue. It read the 7970 just fine, comes up as a 7xxx series card. Then I ran LuxMark Room. My previous Nvidia GT640 ran a 77 on the room, so I was betting this would do a little better... well... Now that's fast. I'll keep reporting back with issues and such if they crop up. I'm curious to see how Photoshop handles the hardware. The expansion slot fan acted up a bit at first, but it is running smoothly at 800RPM now. The GPU temps are incorrect, heat monitor is reporting 85C at all times which is obviously not right. Maybe an SMC reset will fix it or it may just be an artifact of the beta drivers. Hopefully we see even better support as we approach the Mac Pro refresh. Lastly, the power usage doesn't seem too bad at all. I have a UPS that reports wattage. At idle the Mac Pro uses 138W (with one 27" monitor also plugged into the UPS, so subtract about 30-40W from that.) At full load during GPU Luxmark the peak power pulled was 299W. That means the 7970 was pulling 161W + ~15W idle = 176W total GPU load under luxmark. Of course "power virus" programs like Furmark could increase that substantially, but I never use those programs. Hope that helps some people that may want to use AMD cards. Let me know if you want me to test any apps or benchmarks.