3900 MHz (1 core) http://www.cpu-world.com/CPUs/Core_i7/Intel-Core%20i7-3770S.html add +4 using a Z77 board, simply by adding +4 on the cpu multiplier in the bios, that makes 4.3 on 1 core, 4.2 on 2 cores, 4.0 on 3 cores and 3.9 on 4 cores. then oc the bclk as your cpu and mobo can, start off around 104-105 that makes 4.3 x 1.05 = 4.515 then up it slowly and surely, in the OS, +0.2 of bclk each time, saving cpu-z validation file each time, till it freezes...