Have you tried with the voltage at 1.66 and QPI/VTT at 1.355? I've just finished running through a guide to OC-ing and got my system stable after running through a lot of the settings. I have Corsair TR3X6G1600C8D RAM - I'm running BIOS FB and here are my settings - they are overclocked but stable. Also see that there is a link below to the Corsair recommended settings from their forum
BLCOCK ................................... 200
Load Line calibration .................... Level 2
Standard Vcore ........................... 1.25v
Dynamic Vore ............................. +0.05000v
QPI/VTT voltage ......................... 1.355v
IOH Core ................................. 1.100v
DRAM Voltage ............................. 1.660v
Enabled EIST, C1E , other C States
CPU Multiplier = x19
SPD Multiplier = x8
Uncore = x16
QPI = x36
XMP Profile = Profile 1
RAM Set at 8-8-8-24 - everything else on Auto
I tested my system with CPU at x15 (Vcore=normal), and BLCOCK from 150 - 200 with RAM at x6 and x8 - it was stable once I'd increased the QPI/VTT to 1.355 (From the Corsair forum they tested the RAM with QPI/VTT of 1.35 to get stable -
http://forum.corsair.com/v3/showthread.php?s=89e1dacb2680af46b8e7c0f945fafa54&t=81035)
Then to get a higher CPU, I did x21 CPU with Block from 150->180 and that's when I had to up Vcore to 1.25.
I'm sorry if this reads like an OC guide but there are a bunch of other BIOS settings that I'd switched from Auto to a manual setting and I thought they might help.
Feel free to ignore it if I'm talking rubbish - I'm new to OC and manual settings in BIOS.