Up until two days ago, when I updated my graphics drivers, I was able to connect my 4k Sony TV and my 4K LG 27" monitor at full resolution on my 2015 Macbook Pro running Windows 10.
I am using the HDMI Port for the TV and a thunderbolt to HDMI adapter for the LG monitor. I have swapped the cables and the ports around to see if it made a difference, and I have come to conclude that no matter what I do and no matter the combination of connectors, the 3rd monitor that is connected will only allow me to set it up to 1920x1080. I noticed in the AMD Radeon Software > Diplay tab, that Display 1 says it is connected via HDMI and Display 2 says it is connected via DVI-D even though both are connected via HDMI. EVEN when I connect the third monitor to the built-in HDMI port, it will say the 2nd is HDMI and the third is DVI-D.
This causes 2 problems. The obvious one is that I can no longer get my 2 external monitors to use their native resolutions, and the other problem is that when any one of the external displays goes to sleep, it causes some kind of confusion in the driver and wakes the computer back up, causing an endless loop of sleep/wake, that makes my computer act crazy.
I would roll my driver back to the previous one, but this latest version of the drivers insisted upon removing all traces of my previous driver, so I can't just roll back. I don't even know what version I was using that worked before.
I just want to be able to use both of my monitors the way they worked before.