Here's some testing I did using the new Intel approved TjMax=100C for my E8400. I also did this same test with a Q6600 - G0 with TjMax set to 100C and got the same results. I played around with it for half an hour and even took it a little beyond TjMax just to make sure that it was thoroughly warmed up. I tried testing at different temperatures and moved the IR gun around and around but the hottest it would ever show was 5C less than the reported temperature of the hottest core.. This is the gradient that Intel says exists between IHS and the core even when the CPU is 99% idle. The above pic was taken 2 seconds after this one. Once I put it back together I tried doing the RealTemp calibration test. The room temperature near the open computer was 21C and it was running at 1600 MHz and 1.08 volts. With these settings, at idle, an expected core temperature should be about 5C above the room temperature which would be 26C. This is what I get: When using the correct TjMax, and no additional calibration, my core temperatures are being reported about 8C too high. This is a perfect example of "slope error." JohnZS has one core that reads too high and one core that reads too low so a combined error, when uncorrected, of 15C on his Quad is hardly surprising. Intel finally releasing the correct TjMax for 45nm hasn't given the enthusiast community as much information as they thought they were going to get at IDF. Here's a quote from the press release that was posted at Anandtech: "Armed with this information, seasoned application developers and amateur coders alike will finally have everything they need to implement the most accurate, real-time core temperature display tool possible." Well, not quite.