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My friend's laptop suddenly froze, after he rebooted (the machine was given a chance to cool down a bit) he launched an application called SpeedFan and it gave the following:

SpeedFan Screenshot

I was surprised by the number of temperature measurements the program showed, last time I checked (4-5 years ago) I was able only able to see the CPU temperature with a similar application.

Something he said was very interesting "a previous version of this SpeedFan showed only 3 temperature measurements"

So the question is, is SpeedFan making some of the values up? How many temperature sensors does a modern computer usually have?

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closed as not constructive by Dennis, 8088, bwDraco, Tog, ChrisF Feb 11 '13 at 12:16

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

How many temperature sensors does a modern computer usually have? That depends entirely on the computer. But no, SpeedFan won't invent non-existing sensors. – Dennis Feb 11 '13 at 0:17
Instead of the community which really has no access to the source code, the definitive answer is the author of the program to whom you should address program specific this case – mdpc Feb 11 '13 at 0:53
Also the number of sensors would definitely vary from system to system based on hardware installed. Thus no specific real answer can be made to this question. – mdpc Feb 11 '13 at 0:55
up vote 2 down vote accepted

Modern laptops have lots of temperature sensors built-in.

Typically found:

  • 1 in CPU
  • 1 extra in each CPU core (so for a typical laptop of our days, up to 4)
  • 1-2 in GPU (if external graphics)
  • 1-2 in motherboard chipset(s)
  • 1 in each (hard) drive

Some laptops include additional sensors:

  • on the heat pipes
  • battery
  • some spot in the case
  • memory slots
  • raid controllers
  • my Macbook Pro (early 08 model) even got one on the wireless card

Newer Speedfan versions (valid for other software, too) often learn how to read more and new sensors, so finding more sensors with updates is no surprise.

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Would mind giving a source/reference the built-in sensor locations? Thank you – Adi Feb 11 '13 at 0:30
These are locations I experienced (sensors near the memory actually have been new to me, didn't watch any before your screenshot). Can't give you any references, but looking at some specs or googling for speedfan, everest, ... screenshots should get you lots of information on this. – Jens Erat Feb 11 '13 at 0:33

That seems about right. but generally ignore the fire icons, 43 degrees on a laptop is pretty acceptable; in a rack mounted server however, it would be considered very hot.

temp1 is likely a motherboard/case-temp sensor. and CPU is usually an average of the core0+core1 or it may be a third sensor that checks the entire CPU package temp.

DIMM temperature is uncommon, but if speedfan is showing it then likely you have a sensor for it on the system; if the sensor is missing but for some reason speedfan shows it in the list, it will show as 0 or -127 or something obviously wrong on most occasions.

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My laptop (2011 MacBook Pro) has about 10 different temperature sensors on it.

CPU Diode, CPU Digital Core 0, CPU Digital Core 1, CPU Proximity, Integrated Graphics chip, RAM, disk bay, (the actual disk also has a sensor), battery, and there are also a couple more that aren't related to any specific component (case sensors)

The CPU temps are routinely around 90C, since I play games a lot. Idling, on OS X the CPU Diode is about 40C normally, and under Windows it's about 50C. (I'm not sure why, it just runs warmer in Windows. I can feel the case is warmer too, so it's not measuring a different sensor)

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