When connecting a Wasabi Mango UHD420 4K monitor to a Nvidia card that supports 3840x2160, you may encounter black screens at start up. This can be resolved with a change in the monitors OSD if you have the latest firmware for your monitor. The latest firmware can be found here: https://www.wasabimango.co.kr/bbs/board.php?bo_table=down. The page is in a different language and you may need to use a translator to navigate to the correct file. After you have updated the monitor to the latest firmware, open up the OSD controls. Under MISC Menu>FreeSync turn this option to Off. Close the OSD and hard reset the monitor by unplugging the power and leaving it off for 30 seconds. Plug the power back in, reset the computer and any black screens at boot up should be resolved.