

The SFF or MT form factors are a lot better, I’d say MT is the best as it has full height PCIe slots. Keep in mind the dell/hp/lenovo models all use proprietary motherboard form factors and power supplies, but not that big of a deal I think since there are so many parts available if something does break.
I highly recommend 7th gen intel or newer, as you get the much better quicksync support and quality.
If you get a desktop class CPU (i5-7500 for example), the whole computer will typically draw around 15W at idle with an SSD, which is pretty decent.
If you need less idle power draw then you’ll want a mobile/notebook class CPU (like an i3-7100u) as the idle usage should be less than 5W. But those typically only come in the micro/mini form factors.
Also good to remember that every 3.5" HDD draws around 7W when idle and spun-up (typically difficult to spin down on servers since there’s always some process accessing files).







You can try and figure out what’s accessing the array:
fatrace | grep /mnt/mountpoint/This will show you the process, type of access (read, write, open, etc), and path. If you don’t see anything right away just leave it running for a bit.