And if you’re trying to be economical about RAM usage, things like fancy window decorations, window animations, and other purely aesthetic stuff like that can of course go.
That’s negligible at best and imaginary at worst. Themes that aren’t used, aren’t loaded into RAM.
I was playing around with an old laptop dual booting Fedora KDE and W11. And Fedora on fresh boot was using the same/more ram than 11.
Windows compresses RAM these days, not sure if Fedora does by default. Also, by itself Windows is surprisingly RAM efficient. I think it’s a holdover from Windows 8 which was developed for tablets when Microsoft tried competing with iPads.
The problems arise when web views like the news widget load. Then all the past optimizations no longer matter.
Also I don’t think KDE even uses more RAM than other DEs that are designed to be lightweight. Last time I compared, it used the same or less memory as LXDE.
Firefox without any website loaded uses more RAM than a full Plasma session.
XFCE is great for mid-range old devices, and LXQt is great for dogshit old devices.
What’s this device in your scale from old doghit to old mid-range?
Runs a full Plasma session just fine. The problem isn’t the desktop, it’s the web browsers, especially Firefox. Falkon runs OK.
Firefox is absolutely unusable on that PC. Falkon runs much better.