Processing areas of code selectively

I'm making a visualization program with the ability to switch between different scenes, each scene displaying a different kind of visualization. I'm worried about the CPU getting bogged down in calculating all these very different types of scenes. I was wondering if there was some kind of "best practice" for stopping the processing of certain areas of code while that particular scene is not being displayed? Something more elegant than a ton of gates turning metros on and off...should each scene be contained in its own patcher, for example?