System powering off in games, any ideas?

[Spleenus]

Ok, recently I had to change my motherboard and PSU as one of the contacts on the power supply which plugs into the motherboard had completely burnt out the pin on both the PSU and motherboard. So I replaced both the PSU and motherboard and also got a new graphics card.

However since replacing all this I now have a situation whereby in games the system will either freeze or reboot after 5 - 10 minutes. The two graphics cards I've test it with are XFX Geforce 7800GS (new card) and Radeon X800XT PE and the problem occured on both graphics cards so I've deduced that it isn't the problem.

However the PSU should be more than upto the job as it is a hiper 580W jobby and the voltages seem more than stable when I'm looking at them and the system is nowhere near overheating when this problem occurs.

It seems strange that the problem only occurs in games and not in windows when I have tested it with both graphics cards and both give an identical problem.

Any ideas appreciated

edit: thought I should add specs:

proc P4 3Ghz Prescott
mobo Abit AS8-V
ram 4 x 256Mb Geil Value

 

[Dutch Guy]

I would test the system stability with Prime95 and/or Prime95 GUI

And the memory with MemTest (Windows) and/or Memtest86+ (Bootable Floppy/CD)

 

[Xplo]

Have you checked temps?

 

[Spleenus]

Thanks for the replied. I tried the windows memory tester and it found that one of my memory modules was faulty after I thoroughly tested them all. I thought this would solve the problem as afterwards I was able to go in game for about 20 -25 mins with no problems on my ATi card. I then put the nvidia card in and did all the drivers correctly and I got the old problem reoccur. I've put the ATi back in and touch wood there is no problem so far.

Why do all these problems have to happen at once! Argh!