SaberTooth has always been about stability. It's not the best overclocking board. Most significant gains in testing reveal the best performance bump in bandwidth happens @ 1866..
http://www.corsair.com/en-us/blog/2014/march/haswellrealworld
"overclocking increases the effect memory bandwidth has on performance (proving the initial hypothesis), and the jump from DDR3-1600 to DDR3-1866 is the most significant."
"the conclusion is simple: DDR3-1600 isn’t enough for Haswell, and it leaves performance on the table."
"With Haswell I continue to be convinced that DDR3-1866 is the new entry level, and that DDR3-2133 is really the sweet spot. Performance improvements from DDR3-2133 to expensive DDR3-2400 are less consistent, and Haswell’s IMC itself starts to get a little shaky there."