Monitor configuration via xrandr

xrandr - primitive command line interface to RandR extension.

$ xrandr

Output:
=======================================================================
Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 8192 x 8192
VGA-1 disconnected (normal left inverted right x axis y axis)
DVI-I-1 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 376mm x 301mm
   1280x1024 60.0*+ 75.0
   1280x960 60.0
   1152x864 75.0
   1024x768 75.1 70.1 60.0
   832x624 74.6
   800x600 72.2 75.0 60.3 56.2
   640x480 72.8 75.0 66.7 60.0
   720x400 70.1
HDMI-1 disconnected (normal left inverted right x axis y axis)
=======================================================================

'+' - preferred mode;
'*' - current mode.

To change monitor resolution to 1280x1024 and refresh rate from 60 to 75 enter such command:

$ su -c "xrandr --output DVI-I-1 --mode 1280x1024 --rate 75"

xrandr wiki page: https://wiki.archlinux.org/index.php/Xrandr