Screen 0: minimum 320 x 200, current 7680 x 2160, maximum 16384 x 16384
HDMI-A-0 connected 3840x2160+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     33.42*+  30.00    25.00    24.00    29.97    23.98    29.98  
   2560x1440     59.95  
   1920x1200     33.42  
   1920x1080     60.00    60.00    50.00    59.94    30.00    24.00    29.97    23.98  
   1600x1200     33.42  
   1680x1050     33.42  
   1280x1024     33.42  
   1440x900      33.42  
   1280x800      33.42  
   1280x720      60.00    59.94  
   1024x768      60.00  
   800x600       60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       60.00    59.94  
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 3840x2160+3840+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     60.00*+  30.00    29.97  
   2560x1440     59.95  
   1920x1200     60.00  
   1920x1080     60.00    59.94    59.93  
   1600x1200     60.00  
   1680x1050     60.00  
   1280x1024     60.00  
   1440x900      60.00  
   1280x800      60.00  
   1280x720      60.00    59.94  
   1024x768      60.00  
   800x600       60.32  
   720x480       60.00    59.94  
   640x480       60.00    59.94  

Guess I need to switch to DisplayPort for that monitor. :P