Good day! I have a RADEON PRO WX 4100 graphics card and a Samsung U28E590D monitor. Drivers are used the latest version. I can’t set 4K resolution on the monitor. The maximum possible is 1920 x 1080. When I try to configure in manual mode, an error occurs that it is not possible with my monitor. If I use the integrated Intel card, I can set the resolution to 4K.
I have an Acer Monitor that has a higher resolution than 1920x1080. But with HDMI connected I wasn't able to reach to higher Native resolution shown in Windows Display. When I clicked on the higher Resolution it would go black. But I was able to get the higher Resolution using DisplayPort cable.
But depends on the GPU card and Monitor you have installed. I know you can get HDMI 4K now.