I have an E8400 installed at the moment and it is the whole reason that I decided to write RealTemp. The reported temperatures for it just didn't seem right.

The heatsink is off but I've got a small high speed fan pointing towards the CPU.



Some users might think that without a heatsink attached that core temperatures would be out of control but far from it.



They were dead stable for over 15 minutes which was long enough for SpeedFan to draw a complete graph with only brief moments of the temp going up by 1C and then dropping down again.

After 15 minutes of this it was time to get out the IR thermometer. There was no hurry so I had a chance to scan around until I found the highest temperature which was 38.8C.



CoreTemp is using TjMax=105C and SpeedFan is using TjMax=100C.
RealTemp is using TjMax=95C combined with its exclusive Idle Calibration feature.

Have a good look at those 3 programs and you decide which one seems to be displaying the most honest core temperature.

To believe TjMax=105C, you have to go completely against Intel's own in house testing of their processors at idle. Bit 30 of MSR 0xEE is not valid for this E8400.

If you would like to check your own processor you can use CPU-Z and do a Register Dump or you can head to openlibsys.org and download OlsMsrEditor 1.1a. Both programs will let you read MSR 0xEE.