In order to keep the increase in sharpness that you get from 10x the pixels - yes, you would need 10kHz, 10x the refresh rate. The moving picture would look sharper than the moving picture on the 2000px display. If you use 1000Hz refresh rate, then the crispness of moving objects on the 20,000px display would degrade to approximately the crispness of the 2,000px display. I hope that made sense.