Originally Posted by bob saget
36 idle? wow nice. I got two cores at 36 and two at 40 @ 3.6.
I always lap my ihs so that I get perfectly flat mounts with my water block. more than likely why you are getting 4 deg difference across the heat spreader. I had one chip that was such a spoon the temps dropped about 12 deg after I lapped it and gained about 500 Mhz in overclock.
Before lapping I get variations like you are seeing, a few degrees between the cores. After lapping they are usually all the same or maybe 1 deg off but that could just be accuracy of the sensor at that point. I'm not saying you should lap it, I just wanted point out why there are differences in the core temps.