Is it normal my cores are different temperatures?

AdrianPerry

Distinguished
After doing some stress testing yesterday using FurMark Burn-in, i monitored the temps through out the process.

None of the temperatures were unusually high however my cores were each at a different temp. 2 were at about 56 degrees, and the other 2 were at about 45 degrees. Is this normal? Are 2 doing more than the other 2? Or is there something wrong with the thermal paste/heat sink that isnt cooling 2 as much as the other 2?