This question has come up a couple times recently, and after some discussions, I've realized people still aren't sure about the concept of FPS and Physics Timesteps in KSP. KSP is physics bound, and will be for quite some time (if not always). Plus, with 1.1 looming around the corner, now might be a good time to discuss FPS and physics, since 1.1 will definitely have an impact on performance. Additionally, people may misinterpret low FPS in KSP as (by itself) an indicator of poor performa