I've put too much into this iMac, but honestly it's more of a hobby now more than anything. I bought a 2011 iMac 27" 2.7Ghz i5 for $600 last year, and upgraded it as follows: Core i7-2600S 2.8Ghz - $150 2x Samsung 500GB 850 EVO SSDs - $140 each (SATA3 RAID0) 1x PNY 240GB SSD for the SuperDrive bay - $60 32GB (4x8GB) DDR3L-1600 RAM (runs at 1333) - $85 6970M 2GB card - $240 6970 3-pipe heatsink - $35 I've seen all the issues with the 6970M, and I think it's all related to HEAT. So if you're going to install one of these beasts in your iMac, keeping it cool is so important. So learn from this thread and apply the thermal pads in just the way I have shown in the pictures. I'll upload the photos I took showing how easy it is - but you NEED thermal pads and the correct, 3-pipe heatsink to make this work. The 2 pipe is NOT correct - you can see in one of the pics below that the 3-pipe has much larger pipes, and the cooling zone matches the various chips on the PCB. I took 99% alcohol and a toothbrush to clean all the old thermal paste off the 6970M first, before applying new thermal paste. Don't go nuts with the new paste - 1/4" on the die should be plenty. Be sure to remove the protective film on the pads before applying, and apply thermal paste (I use Arctic Silver 5) with a baggie / saran wrap wrapped around your finger to smooth out. It's a pretty easy process once you get the logic board out. I opened Portal 2 at max settings and played it for a few minutes. GPU temp got up to 165 F (apparently it's rated for 200 F) but everything worked great, and it cooled down rapidly. I do notice the 6970M is a fair bit smoother than the 6770M at full resolution - it does offer twice the bandwidth and 4x the RAM after all. Too bad there's no Metal on it. UPDATE: Frickin' thing suffered damage after a power surge in my office building. Welp, it's back to the 6770M again.