Note1: 4PCS= Dual channel, supports 4 modules. Note2: 2PCS = Tested successfully with 2 modules. Note3: The O.C. mode is not guaranteed. It depends on whole system configuration and other parameters. Note4: For system stability, use more efficient memory cooling system to support a full memory load (4 DIMMs) when overclocking. Note5: The mainboard supports DDR3-2000 MHz DIMMs only when you install a 6-core cpu to the mainboard. Note6: DDR3 2250/2200/2133 MHz will operate at DDR3 2000 MHz when OC. Note7: AMD FX series CPU on this motherboard support up to DDR3 1866 MHz as its standard memory frequency. Note8: When overclocking, some AMD CPU models may not support DDR3 1600 MHz or higher frequency DIMMs. Note9: Due to CPU spec, AMD 100 and 200 series CPUs support up to DDR3 1066 MHz. With ASRock design, this motherboard can support DDR3 1333 MHz.