I've had this system for about 14 months now and have constantly battled bizarre behavior regarding the graphics. System: - 12GB G.Skill DDR 3 1600 - ASRock P55 EXTREME4 LGA 1156 P55 SATA 6Gb/s USB 3.0 ATX - 2 x ASUS ENGTX460 DirectCU/2DI/1GD5 GeForce GTX 460 (Fermi) 1GB 256-bit - Antec EarthWatts EA750 750W Continuous Power ATX12V version 2.3 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC "compatible with Core i7/Core i5" Power Supply - Intel Core i5-750 Lynnfield 2.66GHz LGA 1156 95W Quad-Core Processor BX80605I5750 At random times while playing games and during general desktop computer usage artifacts will begin appearing, usually resulting in an un-watchable video or game. Aero will break down, and often the screen goes black and comes back after a few seconds with a notification that the Nvidia Kernel Driver has crashed and restarted. There are lots of people with this problem on Nvidia's forums: http://forums.nvidia.com/index.php?showtopic=207666&st=100. Other than messing with power manage to help, but not solve the problem nobody can pinpoint the issue. Sometimes I cannot boot into Windows at all and need to re-configure the cards in the PCI slots. The system is a lot more stable with just one card installed, although I still get problems in that configuration. Sometimes the system wont boot into windows with a single card in the x16 slot. I need to move it to the x4 slot to get it to boot. Once it does, I will stress test the video card and it will be fine. Temps are good all around, everything is at stock speed. Cpu ranges from 30-75, video cards stress test at about 80 degrees and are completely stable when I test them. I am baffled as to how to diagnose this problem. I've formatted and re-installed all sorts of different driver versions. At first I thought it was one of the video cards, but now I'm not so sure because I can swap out the cards and experience the same issues. I doubt that there is a problem with both of the video cards. 750 Watt Antec PSU should be adequate for my setup with 3 hard drives. Any suggestion on where to go from here other than start buying new components and switching them out? If I start RMA'ing parts (video cards, motherboard) and there is no fault found, what is the punishment usually? I am tempted to replace the motherboard because other people have had stability issues with ASRock, but it's difficult to find a p55/1156 sli motherboard these days. If I want to buy new I will need to replace both the cpu and motherboard with something currently on the market at the tune of around $400. This is not ideal, as the computer is plenty fast for my needs.