Thanks for reading, hopefully you can help: I recently moved from an AM3 motherboard and a Phenom 720 Black edition, to a 1156 motherboard with an i7 860. In doing so, I kept both of my 4870's (1Gb, stock speeds) which worked well in crossfire with my AMD setup without issues (10.5 drivers). However, after setting up my new system, and shutting down after playing games for a short while, it will no longer boot. Sometimes it posts, and shuts down, hangs on windows is starting, or will allow me to play games for a short while (5 minutes) before closing. Temperatures are normal (49~59*C) and my i7 is running at a chilly 30*C, and I have tested both cards separately, removed and reinstalled the drivers many times (10.5 through 10.8), but it rarely boots past windows is starting anymore. On my old system, I used a 650W Corsair power supply, from the TX series, and have upgraded to a 850W, just incase I needed the extra power for the i7. Any help is appreciated, but the strange thing is how on a few occaisions I have been able to play many games, including crysis on very high, but after a shut down, the system will refuse to fully start with both cards again.