I updated to the latest BIOS, the latest video, sound, and chipset drivers.
Here's the problem: Only when playing games after an hour or two, the computer just shuts down and reboots. I'm playing games like Just Cause 2 and Team Fortress 2 at 1980x1080 resolution with everything on maximum settings. After an hour or so, during an intensely graphical situation (like flying a helicopter through a misty jungle and landing) the computer just shuts down without any BSOD and then reboots.
I installed the EVGA Precision software which allows me to control fan speeds on the GPU. The fan speeds are set to go to the max speed at 60 C. During gaming, the GPU temps never go higher than about 60-70 C.
I turned off computer restart in Windows "Startup & Recovery." The system log only records a generic kernel 41 error which I checked on Google and found that it doesn't really point to any particular problem.
My suspicion is that my power supply isn't supplying enough power during full throttle gaming. My Sandy Bridge CPU, as you know, also has a turbo boost mode that ups the speed to 3.8 G when needed. Do you think my new Corsair PSU is possibly defective? I'm thinking of upgrading my PSU to a Corsair 1050w or even a 1200w to see it solves the problem.
If that doesn't solve it, I'm not sure what else to try.
OK, I solved the problem by replacing my PSU with a 1200w power supply. (Cooler Master RSC00-80GAD3-US 1200W) My games run fine now with no shut downs. It seems that under full load, with the GPU fan blowing at full throttle in a high-end game, the PSU recommendations that are often given on system configurators are inadequate. Most vendors say a 850 or 875w power supply is adequate for a GTX 590 and a core i7-2600k, but in many cases, it isn't.
I advise anyone with a GTX 590 to buy at least 1000w PSU.