Hmmm okay so what does it mean when you're 13hr prime95 + memtest stable, but crash after 30 mins of Crysis? I have a Q6600 (G0) on P5Q-E (1003 bios), here are some of my bios settings:

444x8
NB Strap: 333
DRAM freq: 1067
DRAM timings: 5-5-5-15
Performance Level: 10
VCore : 1.45000
PLL : 1.60
VTT : 1.40
VDimm : 2.00
NBCore: 1.30