I just upgraded to a t-bred b and I had the same thing happen to me, allthough with a different heatsink... I have a Thermoengine with delta 38 cfm on a 7v mod, I know the heatsink is aging, but I should not have temps like 57C idle 67C load. I have reinstalled it 7 times, and re applied AS/II 3 times, it seems to be making flush contact with the core, I am not sure what the problem is? and this is at stock temps, with stock voltage. The case temp reads 28C but it is kinda chilly in my room, so i think thats wrong also. when i touch the heatsink when the temps read 67C it is not hot at all, not even warm... before with my old XP 1700+ It seemed to give me accurate temps. maybe its the bios... but i am not sure why it would give me different temps, the mobo has an external temp sensor... it does not read from the core.
I am just a little fed up... but I think that it is lying.