zoli@zoli-P31-DS3L:~$ xrandr
Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DVI-0 connected primary 1280x1024+0+0 (normal left inverted right x axis y axis) 0mm x 0mm
   1024x768      60.00
   800x600       60.32    56.25
   848x480       60.00
   640x480       59.94
   1280x1024_60.00  59.89*
   1366x768_60.00  59.89
zoli@zoli-P31-DS3L:~$ cvt 1366 768 59.89
# 1368x768 59.71 Hz (CVT) hsync: 47.65 kHz; pclk: 85.00 MHz
Modeline "1368x768_59.89"   85.00  1368 1440 1576 1784  768 771 781 798 -hsync +vsync
zoli@zoli-P31-DS3L:~$ xrandr --newmode "1368x768_59.89"   85.25  1368 1440 1576 1784  768 771 781 798 -hsync +vsync
zoli@zoli-P31-DS3L:~$ xrandr --addmode DVI-0 1368x768_59.89
zoli@zoli-P31-DS3L:~$ xrandr --output DVI-0 --mode 1368x768_59.89