After upgrading from an R9 290 to a RX480 my main monitor (4K Samsung U24E590D, connected via DisplayPort) no longer goes into standby. Instead it goes into a loop of briefly going into standby, then turning back on to show a black screen for a moment. When returning to Windows all program windows are rearranged and sometimes the application in the foreground has crashed, as if the PC lost its resolution setting.
This happens with the latest driver versions and regardless of whether the monitor is used as a single or multi monitor. I've also tried different DisplayPort cables without success. While using the R9 290 this issue never happened. Using Windows 10, also tried a fresh install on a spare HD and it also suffered the same issue.
Is there anything else I can try to fix this? Thanks.