1) First you can try the terminal command:
xrandr --output VGA-1 --mode 1600x1200
2) Under settings displays I could not set all the resolutions if the mirror function was marked. If you unmarked this function may be you can set your desired resolution.
1) First you can try the terminal command:
xrandr --output VGA-1 --mode 1600x1200
2) Under settings displays I could not set all the resolutions if the mirror function was marked. If you unmarked this function may be you can set your desired resolution.