Passed >4h of Prime95 Small FFTs with my old L722A Q6600 at 1.44v 9 x 400FSB (shows chip OK) but just couldn't go over a mere 40mins of Blend without system rebooting. Dropped one multiplier to 8x with same settings (shows mobo/RAM settings OK) and it clears, obviously the onboard 4 phase supply can't supply stable enough to keep both chip and mobo happy at the same time or can there any other possible reason/s?

Using a newish Corsair 620HX.