Crysis restarts

[rwillis]

Crysis at all high settings/1024*768 is causing random restarts between 1-5 minutes into gameplay. I know my PSU could be a little better, but I think I have enough power and it has 27A on the 12V rails. I'm using rivatuner to change the GPU fan speed and at 100% and it idles around 50C. What is causing this and how can I fix it...Thanks

Also, how can I see the current temp in game under load?

Windows XP SP2
Athlon X2 6000+ stock
Palit 8800gt 512 stock
2gb 800mhz ram
450W PSU (27 amps)

 

[rwillis]

I ran 3dMark06 and right when the first test finished I checked the hardware monitor in rivatuner and my GPU temp was right under 70...and then it rebooted. What gives?