You may experience a problem with your Dell 4K Ultra HD monitor, connected via the DisplayPort connection, where any open windows get resized and moved to the upper-left corner of the monitor after resuming from a sleep state. The issue has been identified with the following Dell monitor types: UP3214Q, P2715Q,P2415Q with the maximum resolution set to 3840 x 2160 and a refresh rate of 60 Hertz. In addition, non-Dell 4K Ultra HD monitors with these specific settings and connection type experience an identical problem.
To resolve this issue, change the monitor setting refresh rate from 60 Hertz to 30 Hertz.
For monitors like the P2415Q (and most 4K displays), it’s not possible to change the Refresh Rate from within Windows settings. The refresh rates are set by the setting in the MONITOR On-Screen Display (OSD) menu:
The OSD Menu should have options for either Multi-Stream Transport (MST) or DisplayPort 1.2 (DP1.2)
Setting MST options:
Setting DP1.2 Options
Article ID: SLN295708
Last Date Modified: 07/17/2015 08:27 AM