asrock n68c-s ucc manual. . It is not allowed to install a DDR3 memory module into DDR2 slot or install a DDR2 memory module into DDR3 slot; otherwise, this motherboard and DIMM may be. This motherboard provides two pin DDR2 (Double Data Rate 2) DIMM slots and two pin DDR3 (Double Data Rate 3) DIMM slots, and supports Dual Channel.