On three different distributions on one machine, all three running LXDE, Manjaro's is the lowest on resources. It is hard to compare without having matching services on systemd running. I don't know how to get a text file list of loaded running and disabled services to compare. All I know with systemd is the gui of services list and I can only get a screenshot of it.
Looking at the little resource windows on the task bar, even with a browser and a ton of tabs loaded, I can barely see a color line in the bottom being flat. On other distributions I am looking at hills and mountains.