With vsync disabled, my very simple scene renders in 1 millisecond so the frame rate is 1000 fps. Of course I don’t want to waste CPU cycles processing more frames than the monitor’s refresh rate so I throttle the frame rate to 100 fps and free up 9 milliseconds per frame for the CPU. Unfortunately the tearing is unsightly.
With vsync enabled, the same scene renders in approx. 13 milliseconds ( monitor refresh is 75HZ ). No tearing but I lose 12 milliseconds.