My current home server, a Raspberry Pi4 with 4GiB RAM is running out of memory and i wondered whether i could convert my existing desktop PC into a home server. The Pi4 with a SSD connected over USB consumes only 7.1W at idle and 9.9W at load. Before i replace the Pi with the desktop, i wanted to check if it could achieve low power consumption at idle.
It is almost impossible to achieve those numbers, specially the idle, and the load we can only to be close to them when we use the watt/ per-useful-instruction metric.
recentest hw will have decent idle consumption (n95 is around 2w) but the rest of the hw will consume more and usually you attach more powerful/energy hungry devices so expect <10w in idle and perhaps <25w under load.
Older hw could not be so bad under load but they will idle less and will consume more