8800's @ 756MB RAM run @ 60c > 70c under stock fans. This is the general consensus and should not be an issue.

Do you have an independent power line to the 8800? Or are you splitting off a molex? I also note you say the same behavior occurs using on-board VGA. Is that correct? When you test this do you physically remove the 8800?

Interesting about your BIOS CPU temp. Anything over 80c should be an automatic shutdown. Just curious if your BIOS settings are set to an automatic shutdown? If your BIOS even thinks the CPU is running over 90c and if the automatic shutdown is enabled it should shutdown no matter what the real temperature is. This is the BIOS reacting to the BIOS even if the BIOS is incorrect.

Also you might try this little scan and see if 500W is good enough for your system:

http://www.extreme.outervision.com/p...ulatorlite.jsp

Thanks for the fast reply.
My earlier problem occurred with onboard or the 8800, but this was with the memory which was bad. I have not tested to see if this new problem occurs with onboard video.

The 8800GTS that I have has only 320MB of RAM, so should this run a bit cooler than the 756MB version? The card does have an independent power connector.

The BIOS was originally set to turn the computer off if the CPU reached 70C. However, when I updated to the latest BIOS from BioStar this option was set to off. When the BIOS states that the CPU temp is 120C+ programs like SpeedFan report that the CPU Temp is around 30C+ to a high (that I have seen) of 50C. After shutting down the computer I have touched the CPU heatsink (after grounding myself) and found it to be only warm, certainly not hot. When my old computer reported its CPU (a Athlon 2500+ Barton Core) as being 50C I could only touch the heatsink for a second of so, it was so hot. So I really do not think that the problem is with the Temp of the CPU or video card, but maybe with the PSU.

Before I bought this computer I used that powersupply calculator. It said that I need around 380W, which Is why I went with the Raidmax Smilodon (500W).

I misremembered what the powersupply calculator said that I needed. I only need a 321Watt PSU to run my computer.

After reading around some more I have found several posts by people who have similar problems. I think that the amperage must fluctuate. Since the manufacturer of my video card, PNY, states the following: "A minimum 400W system power supply (with 12V current rating of 26A)". I am thinking that this is what is causing the shutdowns, the amps falling short of 26A from time to time. Is there anyway that I can test this? If I switch to onboard video and the problem does not persist, then I have not confirmed that it was the PSU, because it could still be the 8800.

http://www.google.com/search?hl=en&s...S&q=psu+tester