I've been experiencing some odd BSOD issues in Assassin's Creed (just version 1, AC2 works fine) with my Crossfire setup, and some very sporadic crashes in Batman Arkham Asylum (hasn't happened in a while). Temperatures when playing are very civilised, between 60 and 70 for the cards. Minidump says it's atikmpag, a TDR fault. I've tried updating Catalyst, formatting and reinstalling Windows, updating the MB BIOS, returning to stock speeds (for the CPU, the graphics card is never overclocked)... It has other weird behaviours in addition to the games above: - OCCT will sometimes BSOD, and it 'sounds' weird (it's temperature related in those cases, but it's something like the graphics card fan doesn't speed up as smoothly as it should). I can run Prime95 and Furmark for 24 hours with no issue whatsoever, even simultaneously, so I'm not sure what to make of that. It's intermittent, as I've run OCCT for 24 hours at a time with no issue as well. Memtest86 runs for 24 hours with no errors. - a couple of times driver installation hangs in the middle of it, don't know why (hasn't happened since the reformat) - today I updated to Catalyst 10.5 (using driver sweeper and everything) and when it rebooted it said there was no ATI device present. I went to the Device Manager and both cards were disabled for whatever bizarre reason. I've enabled them and are now working - it hasn't locked today yet, but this happens way more often in cold boots than in other situations - Blu-Ray playback is not working in Powerdvd 9, I have to use AnyDVD HD for it to work (but this may be completely unrelated) I'm thinking that there is something amiss hardware-wise, but it's hard to pinpoint what. Any ideas what I should be looking at? This has been going on since I bought the system (a couple of months ago) and I don't know what to do. My setup is: - OCuK bundle i7 920 @4.0GHz with Noctua HSF - Gigabyte EX58-UD5 - 3x2GB Corsair 1600 DDR3 - 2xSaphire 5770 1GB - 2xWD Caviar Black 500GB (not RAID) - OCuK value BD drive - Cooler Master Silent Pro 700W - Antec Sonata Elite case Thanks!