System Gigabyte MA785GM-US2H, AMD Phenom II X2 545 Callisto 3.0GHz, G.Skill DDR 2 1066 memory. When I set memory clock from auto to manual and change memory clock from 4.00 to 5.33, when my system is fully booted and vista 64 premium is fully loaded: after some time I get a blue screen. Not sure why this happens. Any help would be appreciated. Thanks.