That's strange.... my Q6600 is 40 in Coretemp, and 40 in BIOS. I find it hard to believe a 15 degree delta between the two exists. :-/ Um, you said your Case temp was 50 degrees, and CPU temp was 40 degrees. Perhaps the BIOS temperatures are inversed? Try enabling and disabling PECI in BIOS, and also with CPU thermal monistor 2 (TM2).
http://www.tomshardware.com/forum/22174 ... ture-guide
Its based onthe CPU and the BIOS and what is being read
that is why you can not trust what you see all the time
Q9 processors have a bug where the 2nd and 3rd cores read 10c different than cores 0-1
That Toms writeup is generic at best
Intel does not release the data on the procs and unfortunately there can be differences in which you can not ASSUME anything
there is a tCASE, tJUNCTION and tJUNCTION MAX spec
tCASE is typically 10-13c lower than tJunction
Thats one of the reasons why REALTEMP can read 2 different temps or be set to read the tCASE instead of tJ
If reading tCASE it will shift the tJunction delta down by a defined amount to compensate
not all processors are read correctly be it a BIOS, a hardware or other issue.