Old workstation as a daily used server - power concerns UK

These old machines make less and less sense. They consume 1-200W at idle but have less power than a single, modern 6 or even 4 core CPU. So unless you need a ton of RAM or PCIe they are really hard to justify unless your power is dirt cheap.

My ballpark figure would be 100-150W idle for the dual xeon setup. Taking out one CPU would probably drop you 30-40W.

Modern Ryzen still isn't very efficient at idle (at least not for me).

If you're really concerned about power cost: get a used SFF business PC like a Prodesk G4 or something. That'll get you idle draw around 10-15W (and chances are the CPU actually beats the Xeon at most tasks).

I went down the same path as you. I’m based in the UK to. I ended up getting a Ryzen 5 5650g, an ASUs tuf mainboard, 64gb ecc memory on it. It has 2 12tb spinners that never spin down, 4 500gb ssd and 1 256gb Nvme boot drive. Idles at 55W running windows server 2022. When it does something it jumps up to 100W, so what I did was set the cpu to never exceed 50% cpu speed. The cpu clock goes no higher than 2.6ghz. I have a opnsense vm running which provides the internet to the whole house, bt 900 down 110 up. When cpu is running that slow I can still Speedtest at the expected line rate.

I’d say all in all the build cost me around £400, I had the drives and ssds already.

Im very happy with it. I have a NVIDIA p1000 (gtx 1050 equivalent) and I game on it from time to time. When I do that, I set the cpu to use 100% and it is a great little machine. Very happy.

Best thing I noticed with it was the IPC improvements considers to the Xeon v4 system I had before, and at a lower power consumption.

I run a Dell T7920 with dual Xeon Silver 4114, 2 spinning disks and a few SSDs. Idles at 85w with disks spinning and a few Dockers running. 150 to 200w when ripping movies or during data transfers. I don't do anything intensive so I don't have any high usage data.

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.