AFAIK when you load some mission and have FPS shown in something like FRAPS, you can click pause at any time and game does not go anywhere (no menu loaded, its on screen), although your FPS go up by 10-20 when paused, thats because CPU is not used so if you change graphics settings and click "hide" you will see max FPS your video card can output (because CPU is not used on pause). You can see how much your system bttlenecked because of CPU this way.
Is that correct?