Q6600 and VGA problem

[idata]

Hello . my pc info is

CPU : Q6600

MB: Asus P5Q Deluxe

RAM : 2x2GB Corsair 800MHz 5C

Power : 580 with 80% efficiency

VGA : Force3D Ati 4670 HD 1GB DDR3

My problem : In games after 1 ,2 , 3 or 5 min i get this error : "Display driver atikmdag stopped responding and has successfully recovered. (event id 4101) "

After searching i found this solution : I limited cpu to 1 core (system configuration > boot > advanced option > number of processors) , then the problem solved. with 4 cores enabled again , the problem appeared again .

what does this sounds ?

[idata]

Are you running win 7?

[idata]

yes , I`m running win 7 now . but I tested other wins like xp , vista . they were like 7 .