Low power home server hardware?

I bought one of these https://buy.hpe.com/us/en/servers/tower-servers/hpe-proliant... (on sale from Newegg) w/180w external brick, 4core xeon, 16 Gigs of RAM, 1xSSD (Boot) and 3xHDD (SnapRaid) as a NAS/OwnCloud box (and probably more in the future), threw NixOs on it (my first experience with NixOS) and am reasonably happy with the result.

It's compact and quite quiet. One word of warning. It doesn't like to finish posting every time. I suspect the PS might not like all the startup current that all 3 HDD spinning up at the same time brings.

There are some entry level Dells I was looking at as well (that also frequently go on sale) but this one won out.

According to https://www.martinrowan.co.uk/2019/07/raspberry-pi-4-power-t... and https://support.apple.com/en-us/HT201897, an M1 Mac Mini idles at roughly 2x the idle power consumption of a rPi 4 with the default firmware.

My next purchase for my rack is definitely going to be an M1 Mac Mini with the RAM upgrade. This way, I can use it as a build server for Mac, Windows, and Linux (the latter two through VMs) + whatever else I want to run. It's somewhat expensive, but it does literally everything I'd ever need out of a home server.

I would recommend any of the well reviewed units from the "Tiny Mini Micro" series from Serve the Home. https://www.servethehome.com/introducing-project-tinyminimic...

I personally use a Lenovo Tiny M920q purchased used from eBay as a Proxmox node.

I've had good success with the ASRock X470D4U and X570D4U server boards that accept AMD Ryzen CPUs and have ECC support. Just make sure to use the dedicated IPMI ethernet port rather than the shared ethernet port. The shared ethernet port has the nasty downside of losing connectivity during reboot while the dedicated port does not. Note that if you choose the xx00G series of CPUs with integrated GPUs, only support ECC in the Pro models. The xxx0G CPUs have quite good performance in much lower power budgets, hence why they're worth mentioning I've built more than 5 servers with these boards to good success.

I'm curious about why it needs to be low power. The electricity needed for most computers doesn't cost very much, at least not in the US. You could get away with using an old laptop instead of a Pi and difference in cost of power consumption is negligible. You could also check out Mac Minis and SFF PCs as your budget allows. I have a 2009 Mac Mini server with two drive bays. It's not the most powerful thing but it can be yours if you want it.

I just switched to an 8GB raspberry Pi 4 for a ZFS storage solution, so maybe that is an option if you only need a couple VMs?

Are you doing transcoding or other CPU-heavy tasks? If not, Atom chipsets in laptops will be the lowest power consumption that has significantly more RAM than the Pi 4. If you have CPU-heavy load then Ryzen Zen3 generation are the current winners at performance/Watt.

Take a look at Supermicro motherboards. They should have server class Atom-based motherboards, hence low power but with network management, possibility to use ECC RAM, hardware support for virtualization, etc.

https://fit-iot.com/web/products/fitlet3/fitlet3-specificati...

I bought an i7 Lenovo Thinkcentre off eBay and swapped the spinning disk out for an SSD. It’s been great and is pretty much silent. The integrated graphics is even good enough for Plex transcoding.

I've been using an Intel NUC 11 for the past year and it's treated me very well. Small form factor, and relatively low power usage although I've forgotten exactly how much.

I put an ssd in a hp business desktop, i5-6th gen, and it costs $3-4 a month to run 24/7.