Built a small machine using an [Asrock N100DC-ITX](https://www.asrock.com/mb/Intel/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.

The Asrock N100DC-ITX uses a 19v power brick so no separate PSU to power the drives. It comes with a 4 pin cable that splits into 2 SATA power.  The case I chose, Silverstone SG13, comes with a 3.5" HDD bracket but you need to mount the drive belly up so you can screw it in. The second drive I want to put where the PCIe slot is, found a nice 3d model for that. The thing is, the power cable would be too short and the drives would be too far apart to reach both.  So I removed the HDD bracket and cut 2 L-shaped aluminum stripes and I screwed the drive belly down. This way the cable now reaches both drives. I know, I could have cut the cable and made it longer but I prefer to avoid playing with power cables if I can. Turned out quite good. Wanted to share it with other people. Now I need to find someone to 3d print the PCIe HDD holder and find some rubber stuff to put under the L-shapes to dampen the sound of the drive. This is the 3d model, https://www.printables.com/model/385403-pci-slot-hdd-bracket but V2 with the nice feet. PS the drives in the images are broken so I just used them as dummy drives.   That's about it.