A couple of days ago I bought two new monitors (iiyama g-master GB2730HSU-B1), and by doing so I also switched to using display port instead of HDMI (EVGA GTX 970 graphics card).
Now a weird issue has started happening. Whenever I power down the system, a couple of LED's on my motherboard and case will stay on, and my CPU fan and front case fan will keep spinning (though at low speed).
Initially I thought this may have been some residual power, so I waited 5 minutes, but it wouldn't power down. Thinking my PSU may be defecting and leaking some power I unplugged it from the grid/mains. This didn't power down the motherboard either.
After a process of elimination I found out that when I unplug both my display port cables it will power down completely, unplugging a single one doesn't power it down either. Replugging the cables won't power up the motherboard again.
Simply turning off the monitors doesn't work either, though unplugging them from the grid/mains does work.
I am using a MSI b150 gaming m3 motherboard. Operating system is Windows 10 64bit.
I have tried enabling the EuP setting in the "Advanced > Power settings" in the bios. Which yielded no results.