Your TV is only capable of receiving 60hz of info. 120hz/240hz/600hz are all done on a max of 60hz worth of images. They insert additional frames made up by the TV to create 120hz or 240hz of data, or in the case of the 600hz TV's, the create a sort of pulsing affect that is supposed to make it look smoother. These don't work for PC's, which render real time data, as they have horrible latency.