G0 Quad Core Temps - Strange 10-deg difference in cores

[virtualrain]

I tried searching but couldn't find anything so if someone knows a thread where this has been discussed, please let me know.

I've got a G0 Q6600 I'm using on an EVGA build for a friend and it's being cooled by a Fuzion... no matter what I do or how I remount it, cores 1 and 2 are 10-deg cooler than cores 0 and 3.

At idle temps are like 42, 32, 32, 42

At load temps are like 62, 55, 55, 62

Is this a known quirk with the G0?

[LuckyNV]

surface isn't flat, either heatsink or heatspreader, or both.

my B3 is similar.

[xgman]

re-seat then re-measure.