Are u sure mate that your Card isn't faulty ??? I see that ur PCU is ok . I'll sugest to run FurMark for 24 h . then u will see what is going on with ur card . mayge this is cause by overheating . Good Luck
hmmm in this case your card is ok .
there is only one more thing ,
since u are using P5KPL/1600 it means it has G31 on board . and it may have some problems with handling some new cards , especialy 1024 mb ,
I would consider changing mobo for something with P45. any asus P5Q with P45 should be fine .
If there is no other choice it looks like i need new Motherboard. hope this will finally solve my problem . Does anyone have other ideas ???
for sure it is NOT : drivers(disp or chipset) , faulty card , PSU , LCD , overheating or BIOS issue .