Real Temp - New temp program for Intel Core processors

[unclewebb]

ericjia: 1) The problem with getting temperature data from Intel Core processors is that they do not have a typical thermometer inside. They work backwards. As the CPU heats up the Distance to TJMax decreases until it reaches zero. At this point, or about 2 degrees before this point, the processor will start to thermal throttle and try to cool itself down. The formula used looks like this:

Reported Temperature = TJMax - DTS

DTS is the raw data from the digital thermal sensors and TJMax is the temperature where the DTS will be reporting zero.

The problem has always been that Intel has been very secretive about TJMax and until just recently have refused to release this information to users. Intel is calling the numbers they did release recently TJ Target which may or may not be exactly equal to TJMax. For some processors it seems that the two are pretty much equal while for other processors TJMax might be 10C or more degrees higher than Intel's TJ Target numbers.

It doesn't take a rocket scientist to figure out that if you don't have the correct TJMax for your processor then using that formula above is not going to be able to give you accurate core temperatures.

If you open up the Settings window in both version of RealTemp you will notice that one version uses TJMax=95C and the latest version uses TJMax=100C. That's where the 5C difference in your reported temperatures is coming from.

As a programmer, there seem to be so many inconsistencies in the documentation released by Intel that I've decided to ignore it. Intel also admits that TJMax is not a fixed number and may vary a little from one processor to the next, even of the exact same model. TJMax also seems to vary from the left side to the right side of many Quad core processors. Because of all of these problems as well as the sticking sensors that your CPU has, Intel does not recommend using them to report core temperatures. They disagree with programs like RealTemp and they probably really dislike the latest Cool Down Test in RealTemp that shows users just how bad these sensors really are.

I looked up your E5440 and Intel says the TJ Target is 85C. I have no idea how accurate that is. Changing RealTemp and setting TJMax to 85C instead of the present 100C is going to instantly drop your reported temperatures by 15C. Is this accurate? I don't know. Maybe.

The best test that we've come up with to try and prove whether a TJMax value is possible or impossible is by running your CPU at very low MHz and core voltage. The plan is to reduce the heat output to a fixed amount so you can compare to what other users have found. The problem you'll have with this test is that your motherboard may not allow you to set your core voltage manually to a low enough value. For 45nm, I recommend about 2000 MHz and 1.10 volts. If your board doesn't allow manual voltage adjustment then make sure SpeedStep and C1E are enabled in the bios. After you boot up and when you are at idle, your computer should drop down the voltage and MHz to similar values. Use a program like CPU-Z to confirm this.

Try this test and compare your reported idle temperature to your room temperature near your open computer case. 8C to 10C higher is a typical gradient depending on what CPU cooler you're using. Let me know a few more details like that.

2) Holy smokes. So far I've only answered question 1.
At the moment, we can't say anything about your maximum core temperature during this test. Until we are more sure of TJMax, these are just a bunch of numbers.

3) You have no idea how happy I am to finally have got rid of the Chinese symbol. Switching a program after the fact to UNICODE was about an 8 hour pain in the butt just to get rid of that funny looking character. Do you know what it means? I hope I didn't offend anyone with that.

4) I don't think I can do anything to fix problem 4. I've also noticed that issue and will have another look. I might have to momentarily turn off the Always on Top feature when a menu is selected.

For your Cool Down Test, sensors for core0 and core1 are stuck and will be useless. The other two sensors look pretty good. If you can find the correct TJMax, they should give some reasonably accurate core temperatures. Give the low MHz / low voltage test a try.

DJSUB: Yes and no. Intel says the TJ Target for the Q6600 is 90C. My opinion is that TJMax is actually 100C for most Q6600 CPUs that I've seen and maybe even 105C on some / many of the core2 / core3 that I've seen screen shots of. That's why I'm full of doubt when it comes to Intel's release of TJ Target data that has already been quietly updated once. I'm waiting for their next update before I start to believe some of their numbers.