MacBook Pro (15-inch, 2019) with a 4k monitor mis-identifies monitor

displayhdmimacbook prousb

I've got a:

  • MacBook Pro (15-inch, 2019)
  • LG 32UK50T-W 32-Inch 4K UHD (3840 X 2160) with Radeon Freesync Technology and DCI-P3 95% Color Gamut
  • The HDMI cable the monitor came wiht
  • Apple USB-C port dongle providing 4k HDMI and two types of USB ports

All these things claim to be 4k @ 60hz.

My Mac is fully patched 10.15.3

My Mac thinks my monitor is not capable of 60hz at 4k? It actually wants to run it at 1920×1080@30hz but if i choose "scaled" it offers "3840 x 2160 (low resolution)" though still capping refresh rate to 30hz.

What am I missing?

Best Answer

It is most likely still the adapter/cable being used. I had the same issue with an adaptor that claims to run 4K@60 and it didn't. I have the same model for work, and a 2017 model hooked to a Samsung U28E590D and I can get 60Hz using HDMI or Display Port. If what you say is true, and it is an apple adaptor, then you may just have an older version of the adapter which does not support 4K as shown here: https://support.apple.com/en-us/HT207806