I'm trying to find a good stable overclock on the CPU before I go anywhere with the RAM (it's underclocked at the moment).

What GTL settings are good for Quad's?

Right now I'm trying Tony's settings...

A sweet spot you may want to try is VTT 1.4 to 1.44V...GTL1=170, GTL2 95 and NB GTL 85
With high Vcore and NB Voltage.

I notice that if I set 1.535V in BIOS, I get a reading of 1.5 in Windows, and it droops to 1.47 under load.