My Pfsense Box emits a whining Sound (from the CPU) HELP plz



  • Hello,

    I have a problem with my Pfsense box.
    When it is running it emits a high pitched whine, which is very annoying.

    I found an intermediary solution by disabling the HLT feature by entering:
    sysctl machdep.cpu_idle_hlt=0

    That solved the whining problem, but the box is getting hot now.
    I am wondering, if there is another setting, which can be used, to get rid of the whine without adding the temperature.
    Can anybody help me?

    Specs of my Pfsense box:
    Core Duo U2500
    1GB DDR2 RAM
    MSI IM-945GME2
    4GB DOM

    The Box is configured to do inter-VLAN routing at Gbit speeds, so the CPU is necessary :)

    Hoping for answers.
    P.S: Sorry for my bad english.



  • Sound is radiated by physical movement only.
    Given the fact that the CPU is fixed in place and has no moving parts it usually tracks down to the fan of the cooler.
    In your case it seems to resonate when the fan speed is lowered (while the CPU idles and doesn't produce that much thermal waste). Try adjusting the fan settings in the BIOS (if available) to something like "max. cooling". Then it always rotates at full speed.
    If the fan is confirmed to be your problem you should replace it. The sooner the better.
    If it fails completely then your CPU will cook its way to heaven…



  • Hello,

    thank you for the answer, but the device is totally fanless.

    I heard that this is a typical Core Duo Problem.
    The circuits around the CPU tend to emit a whining sound when idling.
    Under Windows XP you can get rid of it by enabling HLT.
    On FreeBSD(Pfsense) it is the exact opposite Oo.



  • Never heard of such a problem.
    If the CPU or surrounding components start creating an audible noise it is time to take them back to the mfrer for warranty.
    They will fail now or in the not so distant future. And if this is a known problem then it seems to be a design error.

    And vibration creates additional heat. If it's the capacitors whining then chances are that they are drying out, losing capacity and stop working as supposed. A complete mb failure would be the result.

    Now try to fix that in software…



  • I think you are getting me wrong.

    There is no audfible noise until I set the HTL value to 1.

    The Board and the CPU are fine and functional.
    And I "heard" the problem from different other boards with Socket M and Core (2) Duo CPUs.

    The noise isn't very loud, but my ears tend to be very sensitive.
    Since my network is based on fully inaudible devices (all devices are passively cooled and equipped with SSDs) there is nothing else to hear then the whining noise from the pfsense box.

    I've tested to disable one of the CPU cores by setting the machdep.hlt_cpus to 1.
    The noise was gone instantly.

    But my goal is to keep the idle HLTing in place by eliminating the noise.
    Is there any software setting to achieve this?

    At present I simply have 2 choices:
    -disabling idle HLT and rising/high temperature and no noise at all
    -enabling idle HLT and normal temperatures -but- whining noise



  • It "could" be the power supply hardware directly around the CPU.
    A lot of power converter circuitry is designed to work at peak efficiency at a very specific load.
    If you switch into idle mode and draw less power it might be that you drop below the operating point and get some physical resonance in the coils.



  • Is it fixable?  :-[

    The noise is very disturbing, because it is the only noise in the room.



  • @Gerinsel:

    I think you are getting me wrong.
    There is no audfible noise until I set the HTL value to 1.

    Nope, got it exactly this way.
    It is still a design error if at some point of operation it starts resonating audibly. And this will damage the device at some point in time - or wear it out sooner as expected.
    What you could do, however, is get it to make noise and touch the parts around the CPU (or whereever sound is radiated from) and see if you can attenuate it.
    Adding your finger's mass and slight pressure should at least tune the frequency. Once you know the parts you could try and add some mass with glueing a rubber feet or something similar to it (soft with a noticable weight).

    This is a physical problem. Try to solve it physically - not with software!



  • @jahonix:

    Adding your finger's mass and slight pressure should at least tune the frequency. Once you know the parts you could try and add some mass with glueing a rubber feet or something similar to it (soft with a noticable weight).

    This is a physical problem. Try to solve it physically - not with software!

    I agree.
    There is an interresting article in the current issue of the c't (german IT magazine) about noises in a PC.
    They have a list of what you have to look for and which materials to use.

    Especially with coils you have to be careful not to use the wrong material or you might end up changing the magnetic behaviour of the coil.
    I'll see if i can post a translation of the relevant parts when i get home.



  • I'll see if i can post a translation of the relevant parts when i get home.

    You can also copy the german text.



  • I have seen this several times before. This is probably caused by resonating coils. You could hot-glue them so they don't resonate anymore but the resonance should not damage your hardware. My Netgear AP makes this sound and my Core2Duo Desktop makes this noise aswell when under load.

    http://forums.anandtech.com/messageview.aspx?catid=27&threadid=2243618



  • Hello again,

    after a long time using the machdep.cpu_idle_hlt=0, I upgraded to 1.2.3RC3.
    The upgrade kicked my custom sysctl.conf, so after the reboot the whining sound reappeared, but its tonal characteristics changed after the upgrade.
    I checked the noise just before the update by changing the value back to "1" and there was no change. But right after the update the noise was more constant.
    It sounds now almost like squeaking sounds.
    So it seems to be more Software related than we thought. :)

    Regards


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