I was having the same issue, fixed it by setting watchdog to 60 and turning on PAL6, or without PAL6 set watchdog to 50..
Phenom II x4 920 @ 3.633Ghz, 4GB 1066 ram, 2 x 8800GT in SLI, Asus Xonar DX soundcard, Logitech G15 + Logitech MX Revolution
