bios go advanved mode-aitweaker-memory auto set to 1600 - save and boot
i had that mobo , and i use RAM 1333 alway's fail if overclock my ram to 1600, that mobo no support VDIM, nothing can be done with this type of motherboard, everyday at 1333( 667) and usually my RAM 1333 can run into 1866 with the Z68, so this type of motherboard is very value ... good luck