I do not think that 8GB can ever be truly stable @1600Mhz+ with a QuadCore on this board, not ever. I have spent a long time trouble shooting and tinkering with things, but unless you are prepared to shove way too much voltage than you aught to into the board (and risk breaking things) I cannot see anything happening.

On a lighter note, I replaced my horrid ram with good quality Corsair RAM which is very happy @ 1.50V CL8-8-8-24 and NB @ 1.27V

I admit I epic failed with my overclocking attempts. Perhaps my QX9650 was a bad chip? or I am pretty crap at this tweaking. Either way I am reasonably happy with 3.33Ghz @ 1.27V (core), 1.20V (FSB Vtt) and 1.51V (CPU PLL).
Any higher and the system loses stability and/or requires way too much volts. For example 10.5 multi (3.5Ghz) requires 1.32 V on the VCore and 1.31V on the NB
That is a big jump in volts for a small increase in Mhz.

If I am honest I would love to have 3.66Ghz stable, but it is just not possible Or at least I do not know how to tweak without hitting notorious BSOD when LinXing. (causing disk errors) if there was a USB bootable Prime95/LinX that would be ace as I could happily tweak skews and GTL (currently using 0/2 = AUTO and 1/3 = +40mV) until I find stability.
John