I'll post my settings here once I've finished another test. One thing that was key for me was the clock skews which I have at normal/300, but I suggest you use trial and error to find your best ones. On both boards I found that delaying the NB more gave me better stability at higher fsb.

On what test does it fail? Large FFTs? If so, I would recommend higher NB volts as it's a bit low imo. Mine is at 1.4 with GTL at 0.62