chcrw

Hey Michael,
 
I actually solved it but I never came back here to update it. It's been super annoying but I managed to figure it out myself.
 
The sound goes away if in BIOS you turn off Intel Turbo Boost but that limits your CPU so you don't want to do that. But that's how I figured it out what it was.
 
If in Unraid you open the Terminal and type the following command, you will see that your cores are almost always at around 2800-3200 MHz, they don't really go down.
watch grep \"cpu MHz\" /proc/cpuinfo  
To fix it, I installed the Tips and Tweaks plugin from the apps tab. Then, in the Settings tab go to Tips and Tweaks, scroll down to "Normal CPU Scaling Governor" and set it to Power Save. Then it should be silence :).

Edit: Ok I listened to my PC again and it doesn't go away 100% but it goes from constantly making noises to every 2-3 seconds, I guess when the CPU goes into a higher MHz. If you disable "Enable Intel Turbo/AMD Performance Boost?" in Tips and Tweaks it's 100% silent but then the CPU is limited to 800MHz.