bfg 6800GT freeze up when 3d games bench running

[smaky]

I need help. I sold my brother my old bfg 6800GT. He can't get it to work. Today I spent 6 hours trying to get it to work.

1. updated mobo drivers
2. used 77.77 drivers
3. new power supply (2x)

The card works great until I try to run 3dmark03, it start out fine but then dumps to 0 fps in about 10 seconds, so does any other 3d game.

Gigabyte k8n pro mobo

So I went and bought a mobo for $30 and the card worked just fine.
The odd thing is that my x850 PE works just fine on his pc. And the 6800 GT works fine on my pc and the new mobo, just can't get it to work on his old mobo which he is in love with. What could it be? If it runs x850PE just fine and I have correctly uninstalled installed graphics cards back and forth on these three pc?

 

[smaky]

When using the new mobo I reused the processor and memory, the only difference was the hard drive. I used a different hard drive to test the 6800GT on the new motherboard. I don't know if that makes any difference.

 

[Tu13erhead]

Try this:
Right click desktop.
Properties.
Settings tab.
Advanced.
Troubleshooting tab.
Disable write combining.
OK.
Reboot.
...
Profit