Memory is backward compatible. You can buy DDR3 1600/1800 MHz. RAM and it will work in the MB. But, you would have to set the speed to it's 'rated' or guaranteed speed from the Mfg. The MB BIOS will default the speed to JEDEC standards (less than 1600/1800 MHz.) If you buy memory rated at 1800MHz., you would have to manually set it to that speed. But, the 1800MHz. memory is compatible with the MB because 'memory is backwards compatible'.