help please

[FullMetal]

I am running one PCI-E XFX 6600 GT on a Asus SLi board. Every thing is running fine except that when I run a game the monitor goes out and I have to reboot. This happens only when I play a game and after only a few minutes. The AGP version has a extra power supply to it, but the PCI-e does not that I can see. ???????? It acts like it is not powered enough? I know it is not the card since this is happening on all 6 of my computers, all exact same hardware and issue?

Help?

 

[gwai lo]

don't PCI-Express slots supply more voltage than AGP?

anyway, could the card be overheating? sounds like it..as it happens consistently

 

[FullMetal]

turn on PC after it is off all day. Run a game monitor goes out. Not run a game monitor fine.
all six are doing this.