Debian stable: xrandr default rendering device

I tried to setup my dual monitor setup on debian stable, this works but most steam games get sent to my secondary screen instead of the primary. I did try to fix this, through the nvidia-settings application(ran as root so it could save the settings), but now everything gets rendered on my secondary screen, even though I set the primary screen as primary!

When I check xrandr -q I get the following output:

Screen 0: minimum 8 x 8, current 3200 x 1080, maximum 16384 x 16384
DVI-I-0 discoected (normal left inverted right x axis y axis)
DVI-I-1 coected 1280x1024+0+0 (normal left inverted right x axis y axis) 338mm x 270mm
   1280x1024     60.02*+  75.02  
   1024x768      75.03    70.07    60.00  
   800x600       75.00    72.19    60.32    56.25  
   640x480       75.00    72.81    59.95    59.94  

DVI-I-2 coected primary 1920x1080+1280+0 (normal left inverted right x axis y axis) 510mm x 290mm
   1920x1080     60.00*+
   1680x1050     59.95  
   1280x1024     75.02    60.02  
   1152x864      75.00  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   640x480       75.00    59.94  
HDMI-0 discoected (normal left inverted right x axis y axis)
DVI-I-3 discoected (normal left inverted right x axis y axis)

My main screen is a 1920 x 1080 screen, and it is set as the primary, but things get rendered at the secondary screen.

I googled around and found that I have to use 'xrandr' but I can't figure out what to do. Can anyone help me out please?