CPU overclocking - GPU instable ??

[fugo]

Hi i hawe problem with my OC X2 4000+ @ 3000Mhz, mem 800Mhz@600Mhz, MB is ASUS M2N32SLI, GPU is EVGA N7800GTX 512MB ram, all with last BIOS, all SYSTEM voltages are up as are in NVIDIA Nforce 590 SLI OC guide ( can send preciously "DU-02451-001_v01_overclocking.pdf" ) the problem is when i run ANY game then my PC frozen in 3-10 mins, maximal time to is freez is cca 30 min - only 2-3 times happen. but is it only in games, when i run 3DS MAX or MAYA, AFTHER EFFECT, or any very CPU intensive task then the PC not freeze..

game freeze: sound looping in cca 0,5 sec and video is stopped, no artefact are seen,

im not entry level user, i work for years with PC so all nessesary thing like drivers, PSU, BIOS update etc are OK. can someone help with this problem ???

P.S. : pc is watercooled

 

[fugo]

even prime95 running on BOTH cores is stable for many hours ( yet about 9 hours and no problem) and the 3DSmax and maya use all resources of PC, rendered for test cca 30Hours. so CPU is stable, unstability has ecountered @3150 MHZ so im running on stable @3000Mhz... somhere i read that DX9 has sometime problems with asigning IRQ to card but GPU is unstable only if i overclock CPU ....