Help needed on macbook pro 2017 + 4K LG 27UD68-W

[xander09]

It is always better to go with Displayport. But now that you already got the hdmi adapter, try this: Go to the Settings on your montior and look for a setting similar to something like „Ultra HD Deep Color“. That Setting has to be turned on to enable hdmi 2.0 and therefore 4k at 60hz.

This helped me track down an issue I was having with the LG27UK600 not showing any resolution options when option-clicking "Scaled" in Display Preferences. I have an unsupported setup, using an eGPU (GT 740 card) hooked up to a 2011 17-inch MacBook Pro to circumvent the dead GPU in the macbook. Which is to say, there are a lot of hacks going on.

In my case, disabling "Ultra HD Deep Color" in the Picture settings menu on the monitor allowed me to set scaled HiDPI resolutions above 1080p over HDMI. DisplayPort wasn't an option as my graphics card doesn't have one, and I don't think the card supports HDMI 2.0, so that's probably part of the puzzle for anyone else with an older graphics card.