I do think it can achieve that while waiting for network packets (see e.g. https://www.anandtech.com/show/16252/mac-mini-apple-m1-tested).
But in terms of money savings it would rarely make sense, as you need to make it back during the time you run the system. If we assume 6 years lifetime then it would only make sense to pay $120 more. But yes, I’d also go for a system that runs regular Linux :)
I don’t have one (and I don’t want one), but Anandtech measured the M1 version at 4.2W in idle. https://www.anandtech.com/show/16252/mac-mini-apple-m1-tested I think you can also get that from other Mini PCs (e.g. NUCs).
I would disagree with idle power not being important for a home server. Most of the time, your system will be doing very little and wait for something to happen. I also don’t think a typical server has a display attached. Wolfang explains this quite well: https://youtu.be/Ppo6C_JhDHM?t=94&si=zyjEKNX8yA51uNSf
I don’t have a Mac Mini, but for always-on systems, the idle power consumption can become quite significant.
If you pay 0.30$/kWh, running your old 100W gaming PC all the time would cost you 263$ per year. My NAS is 45$ per year…
It also depends on what you need/want from the machine. The Mac Mini doesn’t have any HDDs and can’t run a regular Linux distro, for example.
It’s an Apple Silicon Mac Mini. Do you have a particular reason to think the new one is less efficient?