There's a setting you can toggle that drastically lowers cpu usage. Based on what I've heard, the extra weight is negligible since godot is already extremely lightweight (for a game engine).
Go to the Project Settings, enable "Advanced", then go to General > Application > Run and enable "Low Processor Mode".
https://www.reddit.com/r/godot/comments/19adppt/comment/kikldyk/?utm_source=reddit&utm_medium=web2x&context=3
Test out this option to see if it makes things worse noticeable, and if not, then use I guess?
https://www.reddit.com/r/godot/comments/19adppt/comment/kikldyk/?utm_source=reddit&utm_medium=web2x&context=3
Test out this option to see if it makes things worse noticeable, and if not, then use I guess?