It uses less on some of my others, I’m not sure yet why. The amount of folders I’m synchronizing is admittedly fairly large, but they don’t change much, if that somehow helps with advice for my use case.
Other than Linux, there’s not much additional info to work with. Details such as Syncthing version, Linux distro version, number of files being synced, amount of data being syncing all make a big difference.
The RAM usage may also fluctuate heavily, e.g. when scanning and hashing new files, when syncing files, etc. and then drop quite low when doing nothing.
On a side note, I’ve also noticed that the 32-bit i386 version uses about 4x times less RAM than the 64-bit amd64 one (at least on Windows).