Battlefield 3, Frame By Frame
Frame times are far more telling than average frame rates, because slow frames are what break up the immersion of a realistic title, causing you to lose focus, hit a wall, or get fragged. When we require an average of 40 FPS average or at least 20 FPS, we’re actually trying to make sure that no single frame appears on our screen longer than 50 milliseconds. In this test, lower is better (quicker).
Games often start out choppy, but in this case, that choppiness coincides with Fraps firing up. Fortunately, none of those stutters last 50 ms or more.