CPU versus ACPI temperatures?

By meniscus
Apr 7, 2008
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  1. Im using speedfan to monitor my CPU temperatures on my laptop. It reads 41C when laptop is idle. Speedfan also gives me a ACPI temperature reading which is approximately 3-4 degrees higher than the CPU when idle (this fluncuates a little) Both temperatures increase when i start playing games. It seems the reading given by ACPI doesn't increase as linearly with CPU load as the CPU temperature reading.

    I also use Speedfan on my desktop. CPU temperature reading is 43 degees when idle. But the ACPI temperature reading doesnt fluncuate at all! It seems the first reading logged as the ACPI reading remains the value given by ACPI until i restart the PC again!

    My first question is

    What is this ACPI reading? Does it come from a sensor like the CPU reading? If not, how is it calculated? What is it used for? Should i take any notice of it?


    My second question is

    Why does the ACPI reading fluncuate with the laptop and not with the desktop?

    Thanks in advance,
  2. Mictlantecuhtli

    Mictlantecuhtli TechSpot Evangelist Posts: 4,916   +9

    The ACPI temperature you're seeing might be the mainboard's own sensor - maybe chipset?
  3. Whiffen

    Whiffen Newcomer, in training Posts: 323

    Can't always trust temperatures read from software either. Speedfan might be working for you but when I had it it read that my CPU was -10c and my mobo was 120c...
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