Add new resolution for Linux Mint / Ubuntu

jarvis@linuxmint ~ $ xrandr
Screen 0: minimum 320 x 200, current 1024 x 768, maximum 8192 x 8192
VGA1 connected 1024x768+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768       60.0*
   800x600        60.3     56.2  
   848x480        60.0  
   640x480        59.9

jarvis@linuxmint ~ $  gtf 1680 1050 59.9

  # 1680x1050 @ 59.90 Hz (GTF) hsync: 65.11 kHz; pclk: 146.89 MHz
  Modeline "1680x1050_59.90"  146.89  1680 1784 1968 2256  1050 1051 1054 1087  -HSync +Vsync

jarvis@linuxmint ~ $ xrandr --newmode "1680x1050_59.90"  146.89  1680 1784 1968 2256  1050 1051 1054 1087  -HSync +Vsync

jarvis@linuxmint ~ $ xrandr --addmode VGA1 1680x1050_59.90

Then you can choose in the display settings.

To make this valid when next login, add the xrandr commands to .profile:

xrandr --newmode "1680x1050_59.90"  146.89  1680 1784 1968 2256  1050 1051 1054 1087  -HSync +Vsync

xrandr --addmode VGA1 1680x1050_59.90