Okay, you are then going by what would be called tjunction temps. To take the time to explain further, basically a Quad would have 5 sensors.
Tcase - IHS sensor (used by the Bios for health monitor, by speedfan shown as CPU or temp#, or by MB utility app that shows cpu/system temp)
Tjuctions - sensors on the die for the cores themselves, or known as DTS (digital thermal sensors).
Any program, (realtemp, speedfan, coretemp, hd monitor, ect) depend on a tjmax to determine a temp per core. This tjmax is basically a guess by the software maker, and is why you would get different readings from different apps. Some of the programs allow you to offset the tjmax. It is interesting to have a program that gives temps per core, but to me, its not going to be reliable. Even using real temp explains that idle temps will not be accurate:
You should be able to see that message when you click on test sensors.
Now there was suppose to be an article for IDF I believe to explain more on why Intel didn't publish the tjmax, and to better understand how we could get better or more actuate temps on the cores.
To complicate this even more, I went from a MSI P6N Platium MB (NV 650i) to a DFI P35 DK T2RS MB, and the temps are actually acting different, except the Tcase sensor. Normally Idle temps on the Q6600 for the Tcase were about the same, 30C. The cores however, seemed better on the P6N to use a tjmax of 95C, while now I have to use tjmax of 100C on my DFI P35 MB. If I used 95C (which realtemp specifies by default) my core temp readings are lower then my Tcase, which in my mind is wrong.
In the past, you could take the same cpu, and put it into different MB with different temp readings. That was because there wasn't a standard to determine the cpu's temp. Now that Intel wants to perhaps make a standard, even with my Q6600 in 2 different MB, the core readings are different when I was thinking the tjmax 95C was more acceptable.
So, in conclusion, this would be the main reason why I go by the Tcase temp. Also, Intel does publish the thermal spec of all their cpu's. The Q6600's thermal spec is 71C. Its much more simple to go by 1 temp, then try to make sense of 4 temps to understand if your CPU is too hot. Since I over clock some (I not going to go to extremes) what is important to me is not to get to close to 68-70C for the Tcase temp.