Just took the stock heatsink off to see if i can put a thermal probe under. Looks like the spread of AS5 on IHS shows there isn't enough pressure from the stock heatsink mounting mechanism (920D).

Put the thermal probe under and boot up to bios idle temps of 99-101C

Shutt off pc ASAP, and remove stock heatsink and the probe (although very thin) seems to reduce the mounting pressure even more, only the tip of the dab of AS5 touched the stock heatsink's base!

Whether the stock conroe heatsink's mounting pressure is different not sure ???

I did lap the E6600's IHS till the copper showed, so maybe that's why ? No probs with Swiftech G4 Storm mounting, maybe due to spring tension system ?