I tried using the bus instead but didn't lower the multi that far and have been leaving HT at 2000, just gave it a go though:
It does seem more stable at lower vcore
Core: 4.2 GHz
Multi: 14
Bus: 300
HT: 3000
NB: 3000
VCORE: 1.50 v
CPUNB: 1.375 v
Got a maching_check_exception BSOD during IBT with that, going to try a higher vcore now. Just wanted to ask if your changing any other voltages, like NB and RAM or anything else?
I was supprised by how many reviews ignor CPUNB clocking aswell, I learnt about it's benifits from reading forums.