When you disable Vsync you still will not "see" anymore frames than your monitor's refresh rate despite your videocard's ability to draw them. Any frames rendered that exceed the refresh rate are simply dumped in the frame buffer and NOT displayed. Vsync off is only good for benchmarking to test the theoretical output of your card and can cause many visual anomalies or even rubber bullets in some extreme cases. Leave Vsync enabled for stable gameplay. It's probably the most common misunderstanding by many gamers about their video system, primarily because it's focused on bragging rights as to who has the fastest system.
kbman