Any DDR3 RAM above 1366MHz is overclocked; the specific chips on the higher speed RAM are the best of the best from the production process. RAM rated at higher speeds allows the user a "cushion" for overclocking the CPU. Most of us can function quite well at 1366MHz and 1600Mhz (because there is so much of it available). Do get the lowest latencies you can find/afford, that will increase the system's performance (especially in benchmarking software). Most DDR3 1600's seem to be 9-9-9-24, but there are some that are 7-8-7-X, and some 8-8-8-X. I have some older DDR3 1600s that are 7-7-7-21, but they were very expensive.