Cursor stutters every 3 sec. when using LG UltraFine 5K display with 2019 MacBook Pro 16"

Question

Level 1

23 points

Cursor stutters every 3 sec. when using LG UltraFine 5K display with 2019 MacBook Pro 16"

When my new 16" MacBook Pro is connected with my LG UltraFine 5K display the cursor will freeze momentarily twice ever 3 seconds or so. When the MBP is unplugged from the display the cursor behaves normally. When I plug my older 15" MBP into the display it has no problems at all.

After disconnecting and reconnecting the display the cursor seems to behave normally for about ten seconds before stuttering again.

Everything else on the display seems to work fine, video and other motion doesn't freeze, just the cursor. But the cursor is pretty central to using the Mac and the stuttering makes it very frustrating to use.

I was hoping the latest 10.15.5 update would fix the problem but it doesn't seem to make a difference.

I've tried everything under the sun to try to fix the problem (or at least figure out what is causing it): reset NVRAM & SMC, got the highest speed Thunderbolt cable that Apple makes, fiddled with resolution settings, disconnected all bluetooth devices, closed the MBP lid, rand hardware diagnostics, looked at Activity Monitor for CPU overload, turned off "Automatic Graphics Switching" etc. etc. etc. But still, it's jumpy.

MacBook Pro with Touch Bar

Posted on May 28, 2020 6:27 PM

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Answer 1

MoonJ.

Community Specialist

May 29, 2020 3:11 PM in response to itchyrobot

Hi there itchyrobot,

It sounds as though the cursor develops a delay when your MacBook Pro is connected to an external display. You're in the right place to seek a solution, I'd be happy to assist!

Below is a resource that can help:

If your Apple wireless mouse, keyboard, or trackpad isn't working with your Mac as expected

If you need additional assistance after checking out the resource above, based on the troubleshooting completed the next steps would be to reinstall macOS.

How to reinstall macOS from macOS Recovery

Please note, creating a backup of your data before attempting a reinstall is advised. Below is a resource that can provide more information on backing up your Mac:

Back up your Mac

I hope this helps,

Cheers!

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Answer 2

itchyrobot Author

Level 1

23 points

Jun 5, 2020 5:46 PM in response to MoonJ.

My cursor stutters even when using the built-in trackpad, and I've tried disconnecting and reconnecting all my bluetooth input devices and reset the bluetooth module, so it's not an issue with Bluetooth.

I've gone though the process of reinstalling macOS and the problem still occurs. It shows up even on the "set up your Mac" screens, basically as soon as the display is visible it has the stuttering cursor problem.

The only time the cursor doesn't stutter is when the display isn't connected or when the Mac is booted into Safe Mode.

I've also noticed that video with DRM doesn't display (most of the time) when shown on the LG display. Any movies in the TV app play audio, but show as just black. They play normally when dragged to the MBP display. Sometimes after leaving the video on the LG display for a while the video will come back, but I can't seem to figure out any reproducible way to get that to happen.

It feels to me like there are issues with the AMD graphics card driver.

Several users in this thread seem to have had very similar issues, even before the recent 16" MPB.

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Answer 3

itchyrobot Author

Level 1

23 points

Jun 5, 2020 6:57 PM in response to itchyrobot

Here's a video of the stuttering along with a timestamp. The time was created as a webpage and as you can see it's freezing as well.

https://youtu.be/2pI9x7yl1hE

Looking at the timestamps, the cursor freezes around ever 1.9 seconds.

Normal 1.3 seconds > Freezes .15 seconds > Normal .3 seconds > Freezes .15 seconds

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Answer 4

Jun 8, 2020 8:05 AM in response to itchyrobot

itchyrobot,

Thank you for replying back with the updated information and steps you have taken to resolve the issue with your Mac. Based on what you've described, I would encourage you to reach out to Apple Support directly. Below is a resource to get started with Apple Support:

Contact Apple Support

Have a great day!

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Answer 5

itchyrobot Author

Level 1

23 points

Jul 2, 2020 8:05 PM in response to JordanWander

No, the problem is still happening. I'm hoping 10.15.6 will fix it, but who knows.

There are a couple of threads on the MacRumors forums of others having the same issue. One person had luck turning off "automatic graphics switching" in the Energy Saver settings pane, but that doesn't work for most.

https://forums.macrumors.com/threads/mbp16-mouse-stutter-with-external-display.2228049/

https://forums.macrumors.com/threads/macos-stutters-every-2-seconds-when-an-external-monitor-is-plugged-in.2241071/

Since the monitor works ok in Recovery Mode (I mistook that for Safe Mode in my original post) it seems like it's software related and will be fixed in an update soon, fingers crossed. Apparently some kernel extensions aren't loaded in Recovery Mode, so maybe that's what's causing it.

What kind of monitor are you connecting your 16" MPB to? Others in those forums have issues with other models of LG monitors and also with other brands, so it's not just an LG 5K issue.

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Answer 6

esm224

Level 1

12 points

Jul 10, 2020 9:02 AM in response to itchyrobot

On my MacBook Pro 16 5500m 8 gb, stuttering 3 sec.occurs when connecting

professional equipment (blackmagic,kramer,roland).

I think the problem is in the hdcp Protocol.

Connecting to home TVs and Chinese equipment works perfectly.

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Answer 7

maksimt

Level 1

8 points

Aug 1, 2020 3:15 PM in response to esm224

16" MBP 5300M 10.15.5, the cursor stutters consistently using the built-in track pad if my 4k display (QNIX UH3216R) is connected via a Startech DP->USB-C cable.

My 2017 13" MBP doesn't have this issue running 10.14.6 with the same external monitor and cable. I suspect it's an issue with the Radeon drivers or 10.15.5.

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Answer 8

Sep 14, 2020 2:49 AM in response to maksimt

I'm having exactly the same issue with MacBook Pro 2019 16-inch, MacOS Catalina 10.15.6, with LG 5K display. Didn't have this issue before updating to 10.15 and had it so far only with the LG 5K display. It is probably not bluetooth related because even the trackpad of the MB pro itself stutters when the MB pro is connected to the display.

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Answer 9

Nov 16, 2020 7:19 AM in response to itchyrobot

Do you have 3 bluetooth devices connected? I noticed that when I have my Magic Mouse + Magic Trackpad + Bluetooth Keyboard at the same time, my mouse lags every ~5 secs. It only affects the mouse.

If I turn off any of the other devices, like the trackpad for example, the lag stops.

This is happening since Beta 3.

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