CPU temperature incorrect in Dashboard (Core2Duo)

  • I run pfSense on an older Dell Optiplex 380 (SFF, not much larger than a lunchbox). I really like the hardware - it's low power, well-built and tiny. For home use, an E7500 Core2Duo @2.9GHz is more than enough, even for gigabit fios.

    One thing that seems off is the temperature monitor in the Dashboard. No matter what the system is doing, it always reads 55C:


    If I dig in the shell a bit, I find a more realistic number here, but only one one core:

    dev.coretemp.1.%parent: cpu1
    dev.coretemp.1.%driver: coretemp
    dev.coretemp.1.%desc: CPU On-Die Thermal Sensors
    dev.coretemp.0.%parent: cpu0
    dev.coretemp.0.%driver: coretemp
    dev.coretemp.0.%desc: CPU On-Die Thermal Sensors
    dev.cpu.1.temperature: 28.0C
    dev.cpu.1.coretemp.throttle_log: 0
    dev.cpu.1.coretemp.tjmax: 100.0C
    dev.cpu.1.coretemp.resolution: 1
    dev.cpu.1.coretemp.delta: 72
    dev.cpu.0.temperature: 55.0C
    dev.cpu.0.coretemp.throttle_log: 0
    dev.cpu.0.coretemp.tjmax: 100.0C
    dev.cpu.0.coretemp.resolution: 1
    dev.cpu.0.coretemp.delta: 45

    I've verified that the CPU fan is functional and that the heatsink is just barely warm to the touch, so the 28C number is correct. Any ideas?

    Also what's the proper way to ensure that CPU throttling is working? I think it is (going by the dashboard), but wanted to verify. The PC pulls about 65 watts when active, FWIW. I could probably shave 5W or so off of that if I got around to putting in an SSD instead of the spinny disk...

  • Netgate Administrator

    Throttling is working if it shows various frequencies on the dash like that. You can check the sysctl output for est entries cpu.0 that indicate it's using Speedstep rather than ACPI throttling.

    You can add the thermal sensors widget to see all reported cores.

    28C would be very low for the on die temperature on a C2D unless the ambient temp is very low. Something is clearly wrong there though, those values should never be that far apart if nothing else.

    65W is pretty high for a small system like that if that's at idle. I would expect something below 40W.


  • It's in the garage, ambient temp is around 60F...

    As for power, I'm mostly guessing. UPS is showing around 160W total, and drops to 90W or so when I turn off another server, but I'm probably way underestimating the forest of wall wart-powered devices on the power strip.

    Any idea why there is such a huge difference between the temperature reading of the two cores?

  • Netgate Administrator

    Not really. If the value shown never changes at all something is clearly amiss.
    I'm not sure there's anything you can do about it short of swapping the CPU or motherboard.


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