Picked up a Gigabyte GTX 970G1 yesterday. After figuring out I needed the latest web drivers, (and needed to shut off the 970 in order to be able to boot far enough to install them with my old GT120), I got that working. Boots into OS X fine. However in Bootcamp (win 8.1), the card only works for 10-20 minutes in 3D games (Elite Dangerous, Star Citizen). Then the video shuts off and the Mac reboots. I tested with Furmark and it lasts about 2 minutes on the stress test until a crash and reboot. In this case I needed to shut down the Mac completely then start it up again for the card to continue working. I don't use the internal mac PSU for the power ports on the card - I use an external PSU. At first I was running with a 600 watt Corsair for the card. Then switched to a 700 watt Thermaltake I had lying around (I know not the best PSUs but just powering the ports on the card is way under their limit). Also, I had been running a Radeon 7970 with the Corsair that way in the Mac for well over a year with no stability issues. Updated to the latest firmware on the card, didn't help. I also watched the temperature and fan speed while the benchmarks were running, the card never got to any unusually extreme state, maybe maxing at 68 C in Furmark. I was just about to consider returning the card as possibly faulty when I stuck it in a PC case. Doesn't seem to crash after even 15 minutes or so in Furmark. Anyone have any suggestions on why the new card can't seem to handle 3D gaming load in the Mac?