HIS radeon 3870 Issue

[mutalized]

Recently I have been having a huge issue with this GPU. I play call of duty 4, and 5 and I get this issue with both games. The problem im having is during game play I will get a series of lockups involving a very colorful screen, leading to an all black screen and then back just to do it right away. I get a tab that says driver has failed to respond but recovered. It only does it with those games. I am at a loss for how to fix the issue. Ive heard it could be over heating or lack of power to the GPU. It shouldn't be cooling because I have the fan running 100% and my case has 8 fans running. Any ideas or advice is greatly appreciated.

System Specs:
Mobo: Intel made for gateway
CPU: Intel core 2 quad 2.9ghz
GPU: HIS ATI radeon 3870 512mb
PSU: 650 watt
Mem: 4 gig standard ddr2

 

[KSoD]

Do you have the latest set of drivers for the video card? Have you checked the ATi forums to see if there is a known issue with running CoD with the set of drivers you are using?