Option "TwinView" "on"
Option "MetaModes" "1280x1024,1280x768"
Option "SecondMonitorHorizSync" "28-80"
Option "SecondMonitorVertRefresh" "43-60"
Option "TwinViewOrientation" "RightOf"
Спасибо сайту Linuxway. На нём изложена подробная инструкция.
Option "TwinView" "on"
Option "MetaModes" "1280x1024,1280x768"
Option "SecondMonitorHorizSync" "28-80"
Option "SecondMonitorVertRefresh" "43-60"
Option "TwinViewOrientation" "RightOf"
# sudo nvidia-settings
# sudo nvidia-xconfig
# sudo /etc/init.d/gdm stop
# startx
# xrandr -s 1280x800