My New PC Config as following.
MB : ASROCK A75M-HVS
Ram : ADATA DDR3 1600Mhz CL11 (AD3U1600W8G11-B)
HDD : Segate 2TB ST2000DM001BOX
CASE : Cooler Master 343
PS : Cooler Master Extreme Plus 2 475 W
OPD : Lite On 22X DVD-Writer.

All part are new, when boot into the BIOS. the ram speed only show 1066mhz.
If I change the ram speed to 1600 in the OC page, the system can startup and reboot is ok, but will hang in the ASRock logo screen if I restart the system in windows.
If I change the ram speed to 1333 in the OC page, the system is fine but suddenly reboot when I playing flash game.

Now I only use auto (1066mhz) to use the computer. It waste the ram speed, is there anyway to solve this problem? Thx a lot.