Well, I think I've cracked it!

I know you told me NOT to disable Loadline Calibration, but I've disabled it, upped vcore to 1.4v, and all is well. been running bsod free ALL DAY. I played with it all afternoon, and then left it idling tonight. No bsods to greet me on my return.

Temps on NB and SB are 52 and 53 respectively. I have bought a small 40mm fan so that I can cool down NB better.

I am not changing any settings now for a couple of days, to make sure it really is stable.