Thanks Ilia for your comment! I get this output from "xra=
ndr":

"""
Screen 0: minimum 320 x 200, current 5120 x 1440, maximum 16384 x 16384
DisplayPort-0 disconnected (normal left inverted right x axis y axis)
DisplayPort-1 disconnected (normal left inverted right x axis y axis)
DisplayPort-2 connected primary 5120x1440+0+0 (normal left inverted right x
axis y axis) 1200mm x 340mm
   5120x1440     60.00 +  30.00*+
   3840x1080     60.00 +
   3840x2160     60.00    30.00=20=20
   1920x1200     60.00=20=20
   1920x1080     60.00    59.94=20=20
   1600x1200     60.00=20=20
   1680x1050     60.00=20=20
   1600x900      60.00=20=20
   1280x1024     60.02=20=20
   1440x900      60.00=20=20
   1280x800      59.81=20=20
   1152x864      59.97=20=20
   1280x720      60.00    59.94=20=20
   1024x768      60.00=20=20
   800x600       60.32=20=20
   720x480       60.00    59.94=20=20
   640x480       60.00    59.94=20=20
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
"""

So from what I can see only one monitor reported.

But I figured out something else: If I change the refresh rate from 60Hz to
30Hz I get 8W idle power consumption... Umpf... Now I've a big screen, kinda
high end graphics card and 30Hz refresh rate :D It basically works but movi=
ng
windows a little bit faster or moving the mouse pointer around looks
"interesting". Haven't tested any games with that refresh rate bu=
t I guess it
also looks "interesting" ;-)