The specifications call for a vDIMM of 1.65v and QPI volts of 1.475v for operation at 1866MHZ with latencies of 8-9-8-24. With these voltage settings, the modules were rock stable, even when tightening the timings to 7-8-7-24; just a slight increase in the memory voltage to 1.75v was required for stability. This is above the specification of 1.65v set by Intel, but the memory speed is above what most people run as well. By dropping the memory speed to just over 1600MHz, the timings were tightened up to 6-7-6-18. At this level I was able to drop the voltage to the modules to 1.70v, with a reduction in the voltage to the memory controller as well. Ultimately, the highest stable point I could reach was 2021MHz at 8-9-8-24 with 1.84 volts to the modules, and 1.665v to the memory controller; both of these voltages are well above what some would call "unsafe" for the life of your hardware. But hey, this isn't computing for the safe, now is it? Nope! Overclocking takes additional volts to most parts of the system, it's just what level of safe are you willing to live with?