NVIDIA-Linux-x86_64-310.40

おお, nVidia の純正ドライバでも, 画面構成を xrandr で切り替えられるようになっている!

$ xrandr
Screen 0: minimum 8 x 8, current 3200 x 1200, maximum 8192 x 8192
DVI-I-0 disconnected (normal left inverted right x axis y axis)
DVI-I-1 disconnected (normal left inverted right x axis y axis)
DVI-I-2 connected 1600x1200+1600+0 (normal left inverted right x axis y axis) 408mm x 306mm
   1600x1200      60.0*+
   1280x1024      60.0  
   1024x768       60.0  
   800x600        60.3  
   640x480        59.9  
DVI-I-3 connected 1600x1200+0+0 (normal left inverted right x axis y axis) 408mm x 306mm
   1600x1200      60.0*+
   1280x1024      60.0  
   1024x768       60.0  
   800x600        60.3  
   640x480        59.9