Hi Comp. It's been a while. I thought you didn't love us anymore.

For the Core 2 CPUs I've tested, throttling seems to start when the digital thermal sensor is reporting 3 or sometimes 2 so if TJMax is 100 then it does seem to happen at 97C or 98C. I thought this was something Intel did deliberately so the CPU would slow down and keep the core temperature from ever reaching 100C. During my 3 hour Prime95 Small FFT run with the CPU fan turned off, only once did one core touch 100C so I thought Intel's design was working pretty damn good.

I saw a screen shot at X-Bit labs which showed a Core i7 at 99C and it hadn't tripped the thermal throttle bit yet so RealTemp was still showing OK in the Thermal Status area. As soon as that bit gets tripped, even once for a microsecond, RealTemp will display LOG and if thermal throttling is in progress then that changes to HOT.

Based on user feedback, I think the official difference in TJMax between the two Dual Cores within a Quad was increased when the 45nm Quads came out. My best guess is about 5C for 65nm and maybe as high as 10C for the 45nm Quads.

I gave up trying to buy one of every CPU that Intel makes. There's no way I can come up with a large enough sample or even consistent and accurate enough testing procedures to be 100% certain about any of this. Intel knows the truth about their calibration procedures but they weren't willing to tell the whole story at the IDF conferences last year and most users have lost interest in this topic. At least they were willing to admit that TJMax is not a fixed, written in stone value and that some variation does happen and they also admitted to the slope error of these sensors. That was less info than I hoped to get from IDF but realistically, more than I expected to hear Intel admit to.

They were right about one thing. Their Core i7 temperature sensors are much better.