When I choose "better battery life", is my MBP then only switching to another gpu but performing at the same level, or does it also downclock other things like the cpu. I ask because I want to do some video editing on my laptop but since there's no support yet for a GPU in FCE/iMovie, I figure it makes no sense to use the higher performing gpu and just let it run in "better battery", thus also making the laptop run less hot.