Hello /c/selfhosted!

Im sorry if this is not the place to ask but i figured id give it a shot. Mods feel free to delete if i should post elsewhere.

Im currently contemplating building an actual home server. My problem is i have no idea what to prioritize in a server. My main concern is probably power consumption and price. It doesnt really need to be a brast. I currently self host a media center on my gaming rig which id like to move over and id like to be able to host stuff like Immitch and maybe some game servers from time to time.

Im fairly confident in my building skulle since ive built a fair share of gaming rigs over the years but i dont really know whats optimal in a server setting. So i come to you to ask about this landscape.

Im thinking good amount of RAM a fairly recent AMD processor on an unspecified motherboard. I do have an M.2 and extra HDD lying around and also an old GPU (GTX 960) but idk if GPU matters. In any case, how would one go about reducing power consumption, my first idea was underclocking the CPU even though i know AMDs recent CPUs should be pretty efficient. But is there any other, better, solutions to bring down idle consumption?

As stated im pretty fresh on this. Closest ive gotten to a home server is a couple of RPis. Any information or tips are very welcomed!

(Edits: typos)