Update... ZOTAC ZI547 have 2 output ports, 1 DisplayPort and 1 HDMI. My monitor only have HDMI and VGA input. xrandr see HDMI as DP-1. Until now I have connected by this using HDMI cable, experiencing problems with max display, and drm giving "Link Training Unsuccessful". xrandr see DisplayPort as HDMI-2. Now I have changed to use a DisplayPort/HDMI converter to connect to monitor by DisplayPort and HDMI cable. Looks like this is more stable. Brgds Torben