Nick Schermer:
"*sigh* I’m not going to rant on this because as a user you should choose the desktop that makes you happy, but anyway it annoys me a tiny bit. So just to throw some information:
LXDE and Xfce are both based on the same toolkit and provide roughly the same set of features. That as a start makes it technically almost impossible to be much better or worse regarding memory usage. I think this whole myth started by comparing two distributions (clue: strcmp (distro_a + 1, distro_b + 1) == 0).
I’m sure Xfce consumes a bit more memory, because more processes are started. Especially when external plugins are added to the panel: a design decision to make the panel more stable.
I don’t know or care where this comparison started, but if somebody does this again the the future, please compare the actual memory usage and don’t use free. Or even better: don’t compare memory usage at all because it is pretty useless.
That said: if I start a default LXDE and Xfce 4.10 desktop (default Arch Linux packages) and use ps_mem.py, Xfce consumes 2 MiB more memory (same or desktop-equal applications are started). Do whatever you want this is number, as long as you compare apples and apples."