rge: Your testing confirms what I was thinking during some informal testing I did a couple of days ago.
#2395
I'm suspicious that my assumption that a well air cooled Core 2 Duo should run about 5C hotter than ambient at low MHz and low voltage might be too conservative. Maybe our calibration method at low volts / low MHz should be based on 10C.
Looks like the truth is somewhere in between. Your chart will provide users with a baseline when calibrating no matter what type of cooling they're using and I will include this info in the updated documentation with a link to what's been learned during testing.

For a Quad like my Q6600 - G0, I think I would add 2C to your numbers. Time for some more testing.

I've just started comparing power consumption to core temperatures which might help users with calibrating and checking for sticking sensors. Now that we have a baseline it will be easier coming up with answers about Quads, etc. based on power consumption.

By adjusting Clock Modulation in MSR 0x19A, you can also create a nice graph comparing core temperatures at different power levels while running a consistent stress program like Prime95 small FFTs. I'll include this option in the next RealTemp for testing purposes.

Anyone interested in checking this out can use my MSR program to set model specific register 0x19A like this for each core:

12.5% -> 0x12
25.0% -> 0x14
37.5% -> 0x16
50.0% -> 0x18
62.5% -> 0x1A
75.0% -> 0x1C
87.5% -> 0x1E

To return your processor to full power set MSR 0x19A to 0x02

The percentages aren't exact but if you step through different power levels while running Prime you should see your core temps go through different steps. If the temps don't change equally between cores then I think this new test should help confirm sticking sensor issues or maybe even slope error issues. It's a work in progress.