Built a small machine using an Asrock N100DC-ITX motherboard, it has an Intel N100 built in and I also have 1x NVMe and 2x HDDs. The board has a DC Jack so no external PSU.

First time I booted it, the NVMe had Opensuse on it so I played around a little, no problem. When I boot into BIOS also no problem.

When I boot into Unraid, there is a strange sound coming from the back of the board, sounds like an interference sound. I cannot tell if it’s coming from the ethernet port or from the power DC Jack. I think it’s from the power.

I recorded it with my phone and bumped the sound +20 dB, this is how it sounds like. You can hear the fans and that sound. https://soundcloud.com/user-300866676-719653331/n100-1

https://soundcloud.com/user-300866676-719653331/n1002

For power I tried using both an Intel NUC 65w power adapter and an Asus laptop 90w power adapter, the one Asrock recommends on their website. The system has been running for 1-2days, with 4 containers and Home Assistant VM, it idles at around 16w. Without Home Assistant, it drops to 11w.

Any idea what that sound is?

Edit 1: If I go into BIOS and turn off Intel Turbo Boost Technology then it is silent but also kills my performance?

Edit 2 So because I did not want to leave Turbo Boost on, I did some more digging and also realized my CPU was always boosting in Unraid. using “watch grep "cpu MHz" /proc/cpuinfo” it was almost always between 2900Mhz and 3300Mhz. I installed Tip and Tweaks plugin and set Normal CPU Scaling Governor to power saver. The sound is gone and now it seems the CPU goes all the way down to 600 MHz and up to 3400MHz depending if it needs it. I don’t know if the power saver will affect performance in any way but so far so good and I don’t have hear that wheeeeee anymore.

    • @OrangeCorvusOPEnglish
      2•5 months ago

      I thought about it but wasn’t sure. Maybe it’s coil whine coming from the DC plug. Bought the board end of October so I cannot return it anymore. Any tips on how to improve it? Still it’s strange that it’s only doing it in Unraid. In Opensuse I tried to push the system but there was no sound, it just worked. That’s what throws me off.

      • @snekerpimpEnglish
        2•5 months ago

        Don’t know man. I have a 10gb nic that makes different noises depending on if it’s passed through to opnsense or Debian.

        • @OrangeCorvusOPEnglish
          1•5 months ago

          Thanks, didn’t know that. That’s what surprised me, if it was power related, I would have thought it’s doing it everytime.

          • @snekerpimpEnglish
            3•5 months ago

            Electronics are black magic as far as I’m concerned, I just like slapping them together and trying to make them play nice.

      • MaggiWuerzeEnglish
        1•5 months ago

        Why wouldn’t you be able to return it if it shows signs of malfunction within a year?

        • @OrangeCorvusOPEnglish
          2•5 months ago

          Reading about coil whine if that’s the culprit, it seems a lot of manufacturers don’t RMA them. Just googled a little about the topic and they say some GPU manufacturers accept them. In my case with Asrock, dunno.

  • DarkThoughts
    2•5 months ago

    Sounds like coil whining to me too, albeit a pretty loud one. It’s typically GPUs and / or PSUs that are the culprit when they’re under load.

  • @[email protected]English
    1•5 months ago

    Not sure but I’d guess VRM. Would try to localize sound with a mic to be sure. If no RMA or pending FW update, would try disabling problematic c-states and/or dampening with thermal pads.

    • @OrangeCorvusOPEnglish
      1•5 months ago

      I tried to disable c-states and went on a lot of BIOS settings. The sounds is only gone when I turn off Intel Turbo Boost Technology. Then it’s silent but I guess it also kills my performance in Unraid now it shows it at 792 MHz.

      • @[email protected]English
        1•5 months ago

        Nice, sounds like you narrowed it down.

        You can leave turbo boost on and make more subtle adjustments using command line utilities like cpufreq or with GUI-based unraid plugins like this one.

        Before spending time fiddling with settings though, you might try using /sys/devices/system/cpu/cpu*/cpufreq/energy_performance_preference to set one of the built-in profiles like balance_power. If you do need to make manual adjustments, I would try lowering max clock speed first.

        • @OrangeCorvusOPEnglish
          1•5 months ago

          Thanks, I changed something else, before you replied and forgot to update my reply to you, but I updated the main thread. Maybe some else will search for this exact problem so they know what to do.

          So because I did not want to leave Turbo Boost off, I did some more digging and also realized my CPU was always boosting in Unraid. using “watch grep “cpu MHz” /proc/cpuinfo” it was almost always between 2900Mhz and 3300Mhz. I installed Tips and Tweaks plugin and set Normal CPU Scaling Governor to power saver. The sound is gone and now it seems the CPU goes all the way down to 600 MHz and up to 3400MHz depending if it needs it. I don’t know if the power saver will affect performance in any way but so far so good and I don’t have hear that wheeeeee anymore.

  • @[email protected]English
    1•5 months ago

    To me, it sounds like the HDDs. What is anything is using them? Often raids will scan then entire disk at initial setup.

    • @OrangeCorvusOPEnglish
      2•5 months ago

      When I first started building the machine, I only had the NVMe in the board, the HDDs came at a later date. The sound was still present.

  • @[email protected]English
    1•5 months ago

    Power at idle and with Home Assistant running. I assume the noise is when the power draw is higher, but that is unclear.

    • @OrangeCorvusOPEnglish
      2•5 months ago

      The sound is present since the first time I booted Unraid, with only the NVMe, no HDDs and no docker/VMs.