|Your laptop graphics system may not be capable of changing the screen ratio or the resolution to anything different than the integral screen when you are in the clone mode. If your system allows it, try disabling the primary screen. You may then be able to change to better settings.|
Is you laptop screen a wide format? If so, most computer wide screen ratios are 16:9 while most wide screen TVs are 16:10. The native resolution for each screen is dependent on the size of the screen. The larger the screen, the higher the resolution.
No LCD display likes to run in any non native resolution. When the settings are not native, the display is forced to extrapolate, which produces jagged edges.
You need to read your laptop manual to see what your graphics are capable of.