Performance of your game in the editor, vs packaged

Does a game perform differently when packaged? ( mine is lagging in the editor and standalone) so will it perform better when packaged?

The best way to test that is to package it and see. Usually you will see worse performance in the editor than in builds, and usually performance will be worse in development / debug builds compared to shipping builds. However, if you’ve got serious, constant lag in the editor then you should really optimise at that point.