Actually the mobo is fine with most any DRAM 1333 and up in DDR3, would stay away from lower (1066 DDR3)....the big thing will be the CPU, while the mobo can run up through 3000+ sticks, you normally need to look at CPU as the determining factor, a K model 4670K can genrally run up through 3400 and 2666, the 4770K can run even higher, but if you have a non K model best to stick to prob 2133 or less (if you want to run the sticks at their full spec) i.e. if you were to get a i5 4440 chances are it may top at 1866 or maybe 2133 so don't want to spend excess on 2400 or above