I have my second screen set to run at 120Hz by default and the NV control panel set to use the highest available refresh rate when using full screen 3D mode (which switches it to 144Hz). I also have a couple of scripts which I can fire off which change the refresh rate between 120 and 144Hz for when I'm using windowed 3D mode. Not ideal, but better than letting it run 3D clocks all the time.