if your cpu supports ddr3 1333/1600. its likely your motherboard can support much higher frequencies. but 1s you go faster than the cpu 1600 your unlikley to see any performance gains in real world apps. i found its best just to use the fastest ram your cpu supports. which as it stands is 1600
the real difference can be found in latencies, though you can buy ddr3 1600 c9 very cheaply.
but ddr3 160 c7 is very expensive...
if you buy 2200+ c9 ram which costs a little more than 1600 c9 but not as expensive as 1600 c7, you can then run that at 1600 c7 and save a few bux.
not only that the ram will be more efficient and boost system performance by a good 5-7 percent. across the board.