Not *much* difference at least when using the music file (it is also converted into an array of NoteData (custom class with some data like start_time, frequency etc)).
This array is checked every physics_frame (though the whole array is split into the 4 bins for the 4 lanes first, so there are maybe like 90-ish notes per bin per physics_process frame to check). For larger songs this could lead to problems but for this it worked fine :)