I've just OC'd mine to 4.2GHz using a similar board - MSI G45.
Put the frequency to 42
CPU Voltage Core - 1.175
Cores - Fixed mode from dynamic.
Leave everything else to auto. My idle temp was around 28-30 degrees and under stress using AIDA64 60 degrees.
I didn't mess with the CPU ring ratio and just left it at 3.5, and I changed the cpu frequency to 4.2 with a fixed CPU core and everything else is auto. It idles around 31-32 and under full stress load it's setting at 65ish. Not too bad huh? Although...shouldn't my CPU ring ratio be right under my frequency for the gd65?