Use DXTweaker to force tripple buffering on in D3D games, then you can use v-sync and still get a decent framerate.
Needless to say setting your refresh rate to 60 Hz doesn't mean your games will run at 60 fps, it just means they won't run any faster than 60fps, but they can of course run slower, and as said above, v-sync on severely hits your framerate without tripple buffering. If your game takes just over 1/60th of a second to render a frame, your framerate will drop all the way 30 fps if you have v-sync on. That's because there's no buffer available for your game to draw to until the current frame has been displayed.
Turn off v-sync, or use tripple buffering.