Problem using Launcher n other app

Hai guys..im just wondering, r u guys 3650 work find wif the Launcher or other app that running in ur 3650 such as photo id, s.saver and so on. actually all the app work find wif my 3650,but these app a bit strange..when i used it (s.launcher,photo id etc) it used to work fine,but after some time,it decrease my ram memory.As a result, when i try to run other app such as photographer or other app, Memory low and app closed! begin to appeare..i guess its not because of my phone memory,but it might be something to do wif the ram memory..so do u guys know how to deal wif this? Now i cannot use my Launcher o photo id (all the app that running invisiblely),cos the problem will occur.. :-?