[Background Packaging Speed] Is packaging speed affected by UE4 running in background ?

Hey guys, just curious and did not read the source code yet, Is the packaging speed affected by the CPU usage displayed in the screenshot (Editor Preference - Performance - Use less CPU when in background)?

When I switched highlight to another application, UE4 Editor got slowed down, I suppose this will affect the tasks such as python script execution(or other blueprints scripts) and packaging speed? any ideas?