Hi. I'm overclocking my 6950 with MSI afterburner 2.1.0 Original clocks are 800/1250. When I run 3DMark11 with that, it works. Then I overclock the card to 900/1350 and run 3Dmark again. This time it fails (lost window focus) and as the application closes I see the popup in the notification area saying that the driver stopped responding and has recovered. I'm running CCC 11.5. Card is not overheating. Funny thing is, it worked with 900/1350 just 2 hours ago. Worth noting: I was messing with the clocks before this happened, ppl on other forums said their 6950s are running at 950/1450, so I overclocked mine to those clocks too (in steps of 10Hz, no more), testing with GPUTool to catch any artifacts along the way. None appeared, so I left it at 950/1450 and ran 3DMark, thinking I'll get UBER results. What could be the problem? My PSU not supplying enough power? Is it damaged now? It says it can do max 550W, and I also have an Intel quad Q6600 OC'd to 3.2GHz on this system. Motherboard :Gigabyte P35-DS3 CPU: Intel Core2 Quad CPU Q6600 @2.4GHz OC'd to 3.2GHz GPU: AMD Radeon HD6950 shaders unlocked Memory: 2x Ceon DDRII800 2Gb CLS (FSB: DRAM 5:6) PSU: POWER Pentium IV & PFC model LC6550G version 2.0 OS: Win7 Ultimate 32bit HDD1: WDC WD10EADS-00L5B1 ATA HDD2: ST3500 320AS ATA Monitor (not sure if it helps...): AOC 2216 Audio device(integrated): High Definition audio device (lame, I know ) anything else you need?