Overshocked is correct. It is very rare if not impossible to have a multicore CPU have all the same or even very close to the same temperature on all cores. Not all cores on a particular die are going to be the same. When dies are speed binned, in most cases one or more cores limits it to a particular speed bin. Either the core works at a give VID and frequency, but generates excessive heat, or requires a higher than nominal VID to work at a particular frequency (which would also generate excessive heat). So the weakest link sets how the die is sold.
For example lets take a Q6600. When it's die was tested by Intel, tested as a QX6800, the required VID was out of spec for the QX6800 and core 0 generated too much heat. The tester dropped back to Q6700 and now the VID falls in the high end of the tolerance for a Q6700, but core 0 still generates too much heat. So the tester drops back to the nominal specs for a Q6600 and it works within the thermal and voltage limits set by Intel. Intel probably could have sold it as a Q6700, but given it was outside of their own thermal limits for a Q6700, they sell it as a Q6600. Intel laser cuts (or doesn't cut, not sure which) a few traces on the substrate so that it's identified by the motherboard as a Q6600. Now these tests are performed under the assumption that stock cooling is used. Now in the example I used, core 0 was the limiting factor, in fact it could have been any of the four. Also, even though core 0 was our hot core, the other 3 could have had variances in temperature too, just not out of tolerance for a particular speed bin.
I have simplified the testing procedure in the above example somewhat, because Intel also checks the entire range of VID for their dies as well, because this also needs to be identified. Not all Q6600's will have the same VID, but they're guaranteed to fall within a certain range. There are people that swear up and down the lower VID's (more attractive to overclockers) are sold OEM, and the higher end of the spectrum is sold as retail. It seems counter intuitive since OEM is sold cheaper and thus you would think that they would sell them the higher VID's. Another thing to factor in though is the volume sold to OEM's. I don't have any official numbers, but I would guess that less than 10% is sold to retail. Given those numbers it sort of makes sense that OEM's get the lower VID's since this is where Intel makes it's most money even though their margin is thinner.
Hope that helps.
Facebook
Twitter
Instagram