It really depends. I’ve seen PCs that use nonstandard parts just so you must use original parts, and systems which made use of new things like 12 volt only PSU really early and had great designs for easy access in a compact machine.

I use 1 port for management net without vlan, one for WAN and four as a LAG group for all my vlans to go to my switch.

My plex Container has four Cores and 2 GB RAM. Works fine with just one Core transcoding 1080p24 HEVC.

(Ryzen 7 5700G)

Nginx proxy manager, Heimdall Dashboard, Hedgedoc, Your Spotify, pwpush, unifi controller, dmarc reporting tools, zammad and vailtwarden.

Get a used PC, haswell or newer. Those can be found for less than 50 €. Upgrade it to 16 gb ram, install proxmox.

Setting up my own OPNsense router, setting up my own mail server (testing in homelab, then moved to DC as production), Univention Corporate Server as active directory for centralized authentication.

I’ve thrown out my Q6600 in 2020 and that was more than overdue. Deploying any Core 2 doesn’t make sense in 2023 since you can get haswell and newer generations fully built (office PCs) for < 50 €.

I run various haswell i5 hosts, one of them has 84 watts tdp.

i5 4460, 4x 4GB, 1x sata ssd, 2x dual port gigabit lan pcie card. Whole thing draws < 50 watts with 10 % cpu load.