None of the answer of above solve my issue. My PC is working fine and support resolution 2K[NAME]. The problem was solved by disabling standby monitor after x minutes. I think the problem is on driver side. Somehow it cannot wake up after locking the computers desktops. Thank you.
Hi everyone,  I have a issue with my computer Dell XPS 8940 connected to two Dell S2721DGF monitors as dual extended monitors. Sometimes after I lock the screen and came back after lunch break or to start a new day of work, those two monitors won't wake up to enter the password. Sometimes both of them are in Standby or just one. I made upgrade on UEFI (BIOS), replace the graphic card driver(intel UHD 750). I use both monitors at 2560x1440 144Hz because the unit has one DP and one HDMI and the does not support refresh higher than 144Hz. To enter the windows screen I need to disconnect one or two monitors with video cable(DP or HDMI) or restart the PC. Currently I use the latest driver for this type of card. This issue I have from the beginning of use. Even if I use them on 2560x1440 144Hz the issue with Standby is sometimes present. I use only video cables with 4K or 8K transfer. The System is no errors and up to date on driver side. I use Dell SupportAssist to upgrade the drivers. I attached several picture with my system. What suggestion can you all give me to solve this annoying situation? Thank you in advance.    [IMAGE]    [IMAGE][IMAGE]
XPS 8940, two S2721DGF, wake issue