I have recently installed Ubuntu but the drivers from x.org are not so good, because:
- the display with NVidia graphics card (plugged by HDMI) has some problems server x from x.org nouveau driver from xserver-xorg-video-nouveau (open source)
- the second one plugged by DVI to the Intel GPU works just fine.
After driver change to NVidia drivers nvidia binary driver version 470.76 from nvidia-340 (opensource) I noticed that the HDMI display works fine, but the DVI one is just blank and not detected neither by the NVidia x server settings nor the system display settings.