<< Solved >> 10.14.6 RX 560 : can't get HDMI 4k 60Hz working

[alanfranz]

Hello,
I'm using my signature system, and I have got a problem with HDMI. I'm unable to get HDMI 4k working at 60Hz with my LG 43UD79-B. The card starts at 4k 30Hz, and there's no way to select 60Hz.

Displayport works fine out of the box, though.

I'm using an high speed HDMI cable (tested two different cables), the graphics card supports HDMI 2.0, the connected HDMI port in the monitor supports HDMI 2.0: absolutely no luck.

Is there anything I should try changing?

 

[alanfranz]

I solved the problem, I wanted to delete the thread, but may be useful to others.

For HDMI, my monitor had an "ULTRA DEEP COLOR" option. If that option is disabled (10 bit per channel?) the monitor seems unable to support 60Hz AT ANY RESOLUTION (including 1080p) on MacOS.

Still, the feeling of image quality seems a bit lower via HDMI than DP. I have the impression that DP deliver a sharper, cleaner image, I'll do a comparison if I can, next time.