I'm in the process of getting my Home Assistant environment up and running, and decided to run a test: it turns out that my gaming PC (custom 5800X3D/7900XTX build) uses more power just sitting idle, than both of my storage freezers combined.
Background: In addition to some other things, I bought two "Eightree" brand Zigbee-compatible plugs to see how they fare. One is monitoring the power usage of both freezers on a power strip (don't worry, it's a heavy duty strip meant for this), and the other is measuring the usage of my entire desktop setup (including monitors and the HA server itself, a Lenovo M710q).
After monitoring these for a couple days, I decided that I will shut off my PC unless I'm actively using it. It's not a server, but it does have WOL capability, so if I absolutely need to get into it remotely, it won't be an issue.
Pretty fascinating stuff, and now my wife is completely on board as well; she wants to put a plug on her iMac to see what it draws, as she uses it to hold her cross-stitch files and other things.
The PC was drawing ~90W. All solid state, no spinning rust. Lots of fans though, since it's air-cooled. Not entirely sure what was causing the draw, but it's definitely something I want to investigate at some point.
Check your GPU power usage, I remember seeing people complaining about theirs not clocking down if they had a second monitor plugged in, and similar bugs
Worth a look. One monitor uses HDMI, the other uses DisplayPort. They're just cheap secondhand 1080p monitors to get me by until I toss them for an ultrawide 1440p unit.