Apple - 2018 MacBook Pro + LG 4k display = no 60hz
On my Philips 328P6V monitor, using a USB-C to DisplayPort cable with my MacBook Pro (15 inch model from 2019 with Radeon Pro 560X), I first was stuck at 4k@30Hz and couldn't get 4k@60Hz (even though the cable supports it). I had to do two things:
- Enable DisplayPort version 1.2 in the monitor's menu.
- Choose "Resolution: Default for display" in my Mac's System Preferences/Displays.
The first point is pretty obvious, given that DisplayPort 1.1 only supports 30Hz for 4k.
The second point, however, is a bit weird. The original setting was:
And this setting delivered 4k@30Hz. Choosing "Default for display" changed it to 60Hz. After that, even re-selecting "Scaled" keeps my monitor at 4k60Hz.
What I believe might have happened is, that when I had first connected the display, it was still set to DisplayPort 1.1, and I assume my Mac remembered this. Resetting SMC/PRAM didn't seem to help. Switching the Resolution selector in the System Preferences probably made macOS rescan the connection and remember the updated DisplayPort 1.2 capability.
I had the same issue on my MacBook Pro 16". You need to option+click on scaled in display settings and then select 4k resolution. Then tick the box that says "show low resolution modes" and then change the refresh rate to 60hz. Solution found/problem solved.
If this doesn't work its your adapter or cable that is the issue.
So I've tried a few things:
- IOKit/CoreDisplay patch described in this article. But the patch doesn't cover AMD graphics card and is not compatible with the CodeDisplay version I have
- Randomly re-connecting the USB-C/HDMI cable (I've seen comments claiming it works sometimes)
- SwitchResX. It has weird UI, but it works! My display is now recognised as "SwitchResX4 LG Whatever" and does in fact run 60hz. It's not free, but I haven't found a better solution yet.
