lif_andi: If its "30" flat its because you have vsync enabled and your screen refresh rate is 60Hz. Disable Vsync and you'll get higher frames but maybe a little screen "tear" which is not dangerous or bad for your screen like the name suggests.
chaosapiant: vsync locks the framerate at the framerate of the monitor. Not half. If vsync was enabled, then 60 fps is still the highest on a 60hz monitor.
60 fps is the highest you would get, but that does not mean you will get 60 fps.
If you do Vsync without triple buffering, and the GPU cannot deliver frames at 60 fps, you will get no more than 30 fps.