I've never seen that in any book, forum, or code. Usually you want to cap the frame rate for physics calculations but you want the render to run as fast as it can go. The refresh rate is normally the cap but that depends what the user has vsync set to. The video card could care less how fast you render up to a point. Usually in the neighborhood of 600 to 700 fps things start to get a bit wacky (at least my experience on NVidia cards) and start to cause display artifacts. I've never seen any problems with FPS lower than that.
Sure for a speed test thats fair enough, but for practical use you are better off capping the frame rate and have it wait.