I was stuck here until I tried a Northbridge Voltage Mod, with a simple pencil to raise voltage to 1.75v from 1.6v and took her to 540MHz FSB!! Voltage Mod listed under voltage mod section of article.

This is way way ahead of any of the NVIDIA chipset motherboards I've tried so far in terms of FSB capability, I'm thoroughly impressed with the FSB overclocking on this board. You will also be glad to know that I've put the 6-phase Power Management Module for the processor on this board to the test. 6-phase power puts it above the other 650i SLI boards in terms of current load threshold and voltage stability, which is even much more of a concern when you start overclocking a Quad-Core processor on it. One clear indication of robust power would be the voltage swings, especially between idle and load conditions. So I overclocked the processor to 3.2GHz with 1.55v selected (1.53v measured) and measured the voltages during idle and dual-core load conditions. There was simply no fluctuations at all, it remained reading 1.53v throughout the time of testing! The droop is non-existent at this level of load. You can measure CPU Core Voltage below:

This motherboard certainly has a good PWM for the CPU, an important factor that overclockers would want to look out for, and it definitely beats all other 650i SLI motherboards in this department. I would surely advise some airflow over the MOSFETs and Inductors seen above when you're looking to push your CPU.