Underscan problem

Screen 0: minimum 320 x 200, current 1680 x 1050, maximum 8192 x 8192
DVI-0 disconnected (normal left inverted right x axis y axis)
DIN disconnected (normal left inverted right x axis y axis)
DVI-1 connected primary 1680x1050+0+0 (normal left inverted right x axis y axis) 597mm x 336mm
   1920x1080      60.0 +   50.0     59.9
   1920x1080i     60.1     50.0     60.0
   1600x1200      60.0
   1680x1050      59.9*
   1400x1050      59.9
   1280x1024      75.0     60.0
   1440x900       59.9
   1280x960       60.0
   1152x864       75.0
   1280x720       60.0     50.0     59.9
   1440x576i      50.1
   1024x768       75.1     70.1     60.0
   1440x480i      60.1     60.1
   832x624        74.6
   800x600        72.2     75.0     60.3     56.2
   720x576        50.0
   720x480        60.0     59.9
   640x480        75.0     72.8     66.7     60.0     59.9
   720x400        70.1