I recently bought a MacBook Pro 13-inch 2017 and an LG Ultra HD (27UD88) 27" display.
Before buying the display I researched a bit and found no issues in relation to the MacBook Pro.
However, after attaching the screen via the USB-C cable that came along with the display, I only have the option of a 30hz refresh rate.
I've Googled this without finding much – it seems like no one else is having this problem. From a result, I've also learned that my "Display" page in "System Preferences" looks slightly different than a screenshot from an article.
- http://www.lg.com/us/monitors/lg-27UD88-W-4k-uhd-led-monitor (LG official page, shows 60hz)
- https://9to5mac.com/2016/06/04/how-to-enable-4k-60hz-resolution-2016-macbook/ (speaks of a patch needed for MacBook 2016)
- https://www.reddit.com/r/apple/comments/5azoij/2016_macbook_pros_and_lg_27ud88/ (at least one use confirms 60hz with MacBook Pro)
Best Answer
I got it working. I'm not sure exactly how, but here's what I tried, in the order of what I believe fixed it:
(3) was recommended by a user in a forum thread.
Update 2018-01-29
I've since experienced the problem once more, without changing any settings. Attaching/detaching the cable fixed it.
Update 2018-05-06
After the most recent MacOS update (
10.13.4
) it no longer downgrades to 30hz, instead, it never comes on. If the cable is dettached, the computer crashes and has to be booted. So far, the only solution I know of is restarting the computer, which works 50 % of the time, and if not, reattach the cable (it usually won't crash after a restart).This happens after screen sleep and detaching/attaching.
Update 2018-12-13
In this third evolution of the problem (MacOS
10.14.1
) the computer no longer crashes. Roughly 9/10 times it will display in 30hz/horrible resolution and all I have to do (sigh) is detach/attach the cable until I hit that 1/10 where it works. It's a daily 5 minutes routine for me.This setup (MacBook Pro 13" 2017 w/o touch + 27UD88-W) is not recommendable to anyone.