radaja, thanks for doing that. It confirms what I thought, that the lack of air flow inside my case is causing the motherboard to run hot, particularly the NB to beyond 70C in stress testing.

This photo shows why. I've watercooled a Silverstone CW02 HTPC case!



I guess I'll have to pop a fan in there to spot cool the mobo. It's certainly worth doing, so far I've got to 3.8ghz with 1.22vcore which seems fairly reasonable to me.