I used a dual Xeon workstation for a while and it used more power then my entire rack does now. I rebuilt my entire network this year and power consumption was a bit part of the planning process and I don’t believe it limited me getting what I wanted.
best advice is probably to spend a little more and get more modern hardware which will be not only better but massively more efficient. C-States have come a very long way in the last 10 years or so. there seems to be a flood of older dual Xeon workstations on the used market and I think its probably due to their power consumption. they might seem like a bargain but you end up paying for it in power (also heat and noise).
I learnt towards intel for my servers but use Ryzen for my current desktop. but either way I think something more modern will be a lot better. I think intel’s come out on top for efficiency but maybe that is just personal bias.
for numbers:
my dual xeon workstation idled at about 170 watts on its own
my current rack with network equipment/2 servers/a few pi’s/etc… idles at about 140 watts
another tip is to set up homeassistant if your not running it already and get some power monitoring going(shelly products recommended). having data will help you make power decisions and helps with mindset.
currently I have a nvidia 1650 super set up with a passthrough on proxmox then attached to the jellyfin docker container. I have too considered getting an arc as it seems a good deal for thee functionality.
but as someone else has mentioned it can apparently take a decent amount of effort to make it work. if your willing to jump through the hoops then sure its probably a leaning exercise but I decided to just use a cheap older card for now until support is a bit more “out the box” then maybe try again (or the server might get just a hand me down from a desktop upgrade too)
also I don’t really need the upgrade with a 1650 super and a E5-2618Lv4 my use case is more than covered.