Ok, you are doing everything right, however it seems that you should get more out of that stepping though with much lower vcore. There are quite a few 3700+ kab3e running around at 2.9+ @ 1.55V (limited by asus mb's). Try your 10X multi as sandiegos seem to prefer that multi, also, try lower overclocks with less voltage, and bump your vcore up slowly as needed as you slowly raise your overclock, you may just be pumping too much voltage and passing your cpu's sweetspot. Also, what are you stock load temps? Many are getting better temp numbers on stock cooling at similar overclocks. Make sure your heatsink is seated proplerly, and you may want to consider reapplying the thermal paste (preferably as5).