How about Kentsfield Quad-Core Overclocking then?? I put on a Core 2 Extreme QX6700, with stock Intel cooler but replaced the original fan with a delta blower. 

I found it a pity that Gigabyte did not tweak the GTLRef Voltage that improves Quad-Core FSB overclocking. It is still set at a value of 0.66 of the CPU FSB/VTT voltage. Only 330MHz FSB obtained on the Quad Core with this divider for GTL Ref Voltage. However, I did a GTLRef voltage, just on one particular voltage of the 4 GTLRef, GTLRef 1. Exact procedure is described in the Voltage Mod section. 

So modding GTLRef Voltage 1 to 0.7 x VTT instead of default 0.66 x VTT gave me 1.12v with the maximum FSB voltage of 1.6v. I used this combination to hit over 360MHz FSB on Quad-Core.

With still the Intel Stock Cooler but Delta fan, I successfully stabilized the system at 3600MHz for 4 cores with 1.55v set in BIOS:

The CPU PWM is still holding up, as I loaded 4 cores, it was amazing to find that real voltage actually only dropped 0.01v from 1.55v to 1.54v at 3600MHz. If only Gigabyte had tweaked the GTLRef Voltage for end-users in the first place, Quad-Core overclocking would have been a lot better.