15-Inch MacBook Pro Display Stutter with External Monitor

[Droppinoppi]

Hello,

I just got a branch new 2018 15-Inch MacBook Pro (with Radeon Vega 20 graphics) and a Thunderbolt 3 Display (the NEC EA271U). The NEC monitor does not come with a Thunderbolt 3 cable so I got a 1.5ft Nektech Thunderbolt 3 cable from Amazon that is rated for 40Gbps data transfer and 100W PD.

I can observe a visible momentary freeze of the picture that occurs roughly every 3 seconds.

The freeze happens on both the MacBook internal display and on the external NEC display when the NEC display is connected. It happens regardless of the scaled resolution selected for the NEC display (I always left the internal display running at its default resolution).

This happens also when the laptop lid is closed and the external NED monitor is the sole display for the MacBook.

The NEC provides 60W of power over the USB-C cable to the MacBook so the MacBook is always charging and always using the Vega 20 graphics. The 60W is less than the peak power usage requirements of the MacBook Pro (covered by the 87W adapter). The issue still happens when I plug in the MacBook to the 87W power adapter (and verify in the System Report that the MacBook is drawing 87W of power from the power adapter as opposed to 60W from the NEC display).

The issue happens when Graphics Switching is turned off in Energy Saver. All 4 ports exhibit the problem.

I happen to own another 2017 MacBook Pro, which also exhibits the same problem, and a 2018 MacBook Air, which does not have this problem. Based on all this, it does not appear like an issue with the cable or the monitor or the specific laptop.

I am running the latest macOS Mojave 10.14.3 on all three laptops.

I have tried tweaking Energy Saver and other settings on the monitor, to no effect.

Oddly enough, when I return to my laptop and resume it from the beginning sometimes the issue disappears. After switching things around the issue comes back and once there, I am not able to find out a way to get it to go away. I have not been able to figure out under what conditions the issue goes away.

Has anyone else experienced anything similar?

Here are videos demonstrating the issue:

- You can clearly see the picture freeze at .41 seconds.

- You can see the picture freeze exactly every 3.15 seconds three times in this 9-second clip: at
* 1m 09s 13
* 1m 12s 28
* 1m 15s 43

And for those who might question this being a software issue / glitch, here is a video showing how mouse cursor motion freezes as well, and GPU + CPU utilization on the machine, showing there is no system overload of some sort:

Thank you for reading.
[doublepost=1552567261][/doublepost]So it appears the issue only occurs when unplugging the monitor and plugging it back in while the laptop is running.

When cold (re)booting the laptop from power-off or resuming from sleep with the monitor cable already plugged in (and most of the time when plugging the cable in for the first time after a cold boot/resume) the monitor works fine - there are no 3.15 second periodic freezes / stutters.

Disconnecting the monitor and reconnecting it again while the laptop is running causes the 3.15 stutters to begin. Every. Single. Time. (The stutters only happen while the external monitor is connected).

Note: I do not possess any Thunderbolt 3 to DisplayPort or HDMI adapters to test other connectivity options. I do not have other external monitors in my possession to test either. I am planning on visiting an Apple Store and asking for help to test for this problem using the Apple Store-offered LG monitors) using my laptop and my thunderbolt 3 cable.

 

[leman]

Haven't seen anything like this with any of our 2018 MacBook Pro. Just a minor detail: the display you bought is not a thunderbolt 3 display. It uses regular display port over the USB-C connection (USB-C natively supports DP).

 

[Droppinoppi]

Update 2: Had a chat with Apple Support, they had me reset the SMC controller, which did not help, and I am set for an appointment in the store tomorrow.
[doublepost=1552571138][/doublepost]

Haven't seen anything like this with any of our 2018 MacBook Pro. Just a minor detail: the display you bought is not a thunderbolt 3 display. It uses regular display port over the USB-C connection (USB-C natively supports DP).

Thanks for sharing your experience and the clarification about the display not being a "thunderbolt 3 display." I am trying to make sense of it all and it seems all displays are DP-over-USB-C connector using a Thunderbolt 3 cable usually (as it needs to be rated 20Gbps at least if you want 4K UHD 3840x2160 video at 60fps with 30-bit color adds up to >15Gbps which is above the USB 3.1 10Gbps speed).

Other than older monitors that I have heard about that used to be able to daisy chain using prior versions of Thunderbolt, are there any current monitors that actually use any Thunderbolt 3 functionality (for daisy-chaining or for picture data transfer) vs just doing DP over a USB-C connector cable that is likely rated to support Thunderbolt 3 speeds?

 

[jaytv111]

There's pretty much 3 Thunderbolt 3 monitors out there: LG Ultrafine 5K, LG Ultrawide 5Kx2K, and a Samsung. The rest are USB-C. https://9to5mac.com/2018/12/11/best-4k-usb-c-displays-for-macbook-and-macbook-pro-2018/

It could be a cheap cable problem. There is an Apple Thunderbolt 3 cable you could try out and return it.

Interestingly there were problems with the LG Ultrawide and the Macbook Pro, but it was with the 560X GPU. https://9to5mac.com/2018/11/26/revi...mac-mini-macbook-air-pro-thunderbolt-3-video/

 

[Droppinoppi]

There's pretty much 3 Thunderbolt 3 monitors out there: LG Ultrafine 5K, LG Ultrawide 5Kx2K, and a Samsung. The rest are USB-C. https://9to5mac.com/2018/12/11/best-4k-usb-c-displays-for-macbook-and-macbook-pro-2018/

It could be a cheap cable problem. There is an Apple Thunderbolt 3 cable you could try out and return it.

Interestingly there were problems with the LG Ultrawide and the Macbook Pro, but it was with the 560X GPU. https://9to5mac.com/2018/11/26/revi...mac-mini-macbook-air-pro-thunderbolt-3-video/

Thank you for the input jaytv111.

I am still interested in hearing some backing to the Thunderbolt 3 vs USB-C monitor claim.

What makes a monitor qualify as a "Thunderbolt 3" monitor? Given that based on everything I read out there, the only way people send video over USB-C cables today is via the DisplayPort protocol, which natively runs alongside both the USB 3/3.1 protocol and the expanded-capabilities Thunderbolt 3 protocol. Or is there a native Thunderbolt 3 protocol for driving a display? Or is it simply that the monitor has something akin to a built-in Thunderbolt-3 dock that passes through DisplayPort data to the Display and has USB ports that can run at high speed? (My NEC caps USB port speeds to USB 2.0 speeds and if I want USB 3 speeds I have to give up 4K UHD at 60Hz and downgrade to 30Hz which is naturally unacceptable).
[doublepost=1552587860][/doublepost]

It could be a cheap cable problem. There is an Apple Thunderbolt 3 cable you could try out and return it.

It sure could, although it would be strange that the MacBook Air is able to drive the monitor no problem at the same resolution and same refresh rate with that same cable (using its much weaker Intel integrated graphics), while two MacBook Pros with two generations of different discrete AMD graphics fail to do so properly (under certain conditions).
[doublepost=1552589289][/doublepost]So I guess the best way I can answer my "Thunderbolt 3" monitor question is with the following quote from the LG UltraFine 5K product description: "Plus, three USB-C downstream ports (USB 5 Gbps) let you connect additional devices as needed."

As I already mentioned, the ports on my NEC EA271U are limited to USB 2 speeds (480 Mbps) unless I downgrade from to 30Hz (at the max 3840x2160 resolution), and I guess the reason for that is that the monitor is only capable of using USB 3/2 + DisplayPort over the USB-C cable and that cannot carry as much data as Thunderbolt 3 + DisplayPort can.

These protocols are so vaguely documented online that it makes my engineer heart cringe. If I can run DP alongside USB 3 over my USB-C link, then who determines the maximum speed? Does the DP data count towards the USB 2/3/3.1 data rates of 480Mbps/5Gbps/10Gbps? How does that make sense since the protocols are independent and running alongside each other as mentioned in some articles online?

Okay, now this is making some sense:

"Thunderbolt 3 is bi-directional with four lanes of PCI Express Gen 3 and eight lanes of DisplayPort 1.2."
- https://thunderbolttechnology.net/blog/difference-between-usb-c-and-thunderbolt-3

What does USB 3.1 support?

"4K @60Hz 24-bit color (without compression) with simultaneous USB 3.1"
- https://www.displayport.org/displayport-over-usb-c/

Okay, so if my display is 4K 30 but using 30-bit color maybe that is why it caps USB to 2.0 speeds (that option is not listed in the article above, but the next option kind of caps things as 4K with 30-bit color might fall somewhere between 4K and 5K with 24-bit color:

"5K (5120 x 2880) display support without compression with simultaneous USB 2.0"

Hope this is might be helpful to others looking for the same info.

 

[Droppinoppi]

It could be a cheap cable problem. There is an Apple Thunderbolt 3 cable you could try out and return it.

Just tried Apple's 0.8m Thunderbolt 3 cable. Problem still exists. Displays still stutter continuously every 3.15 seconds after reconnecting the external monitor while the laptop is running.

 

[Droppinoppi]

I was at the Apple Store today. Connected to an external 21.5" LG UltraFine 4K display using both USB-C Thunderbolt cables in my possession - the Apple one and the cheaper one from Amazon. Both times the LG worked flawlessly, no stutter whatsoever after disconnecting and re-connecting the cable several times.

At home, the NEC monitor still exhibits the issue every time I disconnect and reconnect it without putting the MacBook to sleep. I have decided I really like the NEC monitor and will work around the problem for the time being - putting the computer to sleep for 30 seconds resolves the issue every time.

My support rep at the Apple Store was really nice and took the time to take detailed notes on my case and escalate to Apple Engineering.

I am going to be in touch with NEC support as well over the next few days. Will keep this thread updated for the benefit of anyone else out there who might be running into the same issue.

 

[masondoesthis]

Thank you!

I'm having the EXACT same issue!

The Apple store had me do a fresh install after the MacBook passed all of the hardware tests. It did not help!

Just hearing someone have the same problem has helped though. Thank you for posting.

Any updates?

Also, for me, going to sleep for 30 seconds makes everything worse.

 

[Droppinoppi]

Hi, glad my post helped. I have no updates. The issue remains on the latest macOS update and I am living with it.

What external monitor do you use?

Thank you!

I'm having the EXACT same issue!

The Apple store had me do a fresh install after the MacBook passed all of the hardware tests. It did not help!

Just hearing someone have the same problem has helped though. Thank you for posting.

Any updates?

Also, for me, going to sleep for 30 seconds makes everything worse.

 

[masondoesthis]

I'm plugged in to a Decimator MD-HX to convert from HDMI to SDI and then into a video switcher. I did just find out that plugging the same HDMI cable directly into an old monitor we had around did NOT produce the same issue. Not that that really does anything for me though.

 

[masondoesthis]

Hahahaha.
This morning I had a friend come into the office and plug their 13-inch Pro into my setup just for kicks and it runs FINE! Plays everything, no stuttering.
Hahahaha.

Also, I wanted to ask you, can you play Netflix movies on Safari on that laptop? After finding that I can't, I followed another thread's advice and added a key to the NVRAM. It has apparently helped a lot of people, but did not work for me. Might be worth a shot? It's easy enough to find.

 

[JordanWT]

Just wanted to chime in to say the same is happening to me. Late 2018 MacBook Pro 15" with Radeon 555X. Rebooting or going to sleep, with or without the monitors plugged in doesn't change anything (I have two 4K monitors connected via HDMI -> USB-C adapters). Problem disappears when unplugging both monitors and using only the built-in display.

The picture freezes just like you illustrated in your videos, although sometimes I can go for longer (or shorter) than 3.15 seconds. I hadn't really noticed until I applied the latest updates this morning. It might have started with the update, or the update made things worse, I'm not sure.

It doesn't seem like a big deal but it gets annoying really fast.

[update] Issue went away today when rebooting my computer to install a completely unrelated driver. Previous reboots didn't change anything, plugged in or not, but today it seems that after rebooting the issue is gone. I have not seen a single unexpected lag. Will update if the issue comes back.

 

[bobsbobs]

hi,

did anyone get any answers with this problem?

im having major issues with Resolume software dropping frames when plugged into a decimator (hdmi to sdi convertor) via a t3 > hdmi convertor. also problems going hdmi to dvi into a video mixer.

I have a feeling its a mohave/Vega problem

b

 

[darenfoh]

Hey Bob, saw your reply and had to sign up...and thank you Drop for starting the post...

I have a 2018 MBP with 560x inside and I am having the same issue as you are. I am in the live entertainment industry as a video engineer and I plug my MBP into switchers all the time and have experienced this every three second stutter. I have been in contact with Analog Way which is one of the switchers that I commonly use, and they told me it's possibly a HDCP issue. I spent an hour with an Apple Senior Advisor over the phone for about an hour going through numerous steps.

What I found is that with HDCP enabled in the switcher, my MBP does not stutter but I can't get a picture from my MBP. But with HDCP turned off (which is what you normally do to get a picture and bypass HDCP) I can get a picture but my MBP stutters every three seconds.

This problem exists for the Analog Way switcher and also a Roland Switcher as well and it doesn't matter what adapter or cable you use and doesn't change when you restart. I've tried everything and even the Senior Advisor is puzzled.

Me and the Senior Advisor also think that it may be a T2 Chip problem as well. I have downgraded to High Sierra and have yet to test it again with a video switcher to see if it is in fact Mojave that may be causing it (Apple told me it can't be done because my MBP was supposed to be shipped with Mojave but there was a way. I have also called a friend that owns a 2018 MBP as well and he is still on High Sierra with no issues.

I did in fact find a work around when I was still in Mojave. I used a video converter like the cheap Monoprice HDMI to SDI converters and the problem went away. It may even work with an HDMI splitter that bypasses HDCP.

I encourage anyone that has this issue to call apple and report it to get a fix going. It is definitely hurting us professionals that use high end displays and video switchers

Hope this supplied enough information. I will regularly check this thread to help anyone out.
[doublepost=1561050351][/doublepost]

I'm plugged in to a Decimator MD-HX to convert from HDMI to SDI and then into a video switcher. I did just find out that plugging the same HDMI cable directly into an old monitor we had around did NOT produce the same issue. Not that that really does anything for me though.

Did the problem go away when going into the decimator first?

 

[stylinexpat]

I am running mine with a LG Ultra Widescreen. Have not noticed that problem yet. The only problem I have sometimes is compatibility in reopening the 3 separate windows back up in the same place on the monitor

 

[bobsbobs]

hey mr d

glad im not going crazy, im running my show on my mbp retina late 2015 and the £4k 2018 mbp is benched until this issue gets fixed

decimator definitely does not strip hdcp, I get the same problem going hdmi > decimator > sdi

the lag even happens when I plug only my hdmi detective with hd resolutions programmed into it.

I spent 2 hours in our local store demonstrating it with it directly plugged into a lovely small hd monitor via hdmi with problem still persistent

they could not help me at all and suggested I try installing high Sierra myself as they were not authorised to do it. I have found it impossible on my model of mbp to do that, on my own that is

they did tell me that if they plugged into their monitors at resolutions of their choosing they would see the problem as mine as im doing something that the computer was not designed to do..... I did tell them that suggesting the 2018 was not capable of plugging into professional broadcast equipment that was a huge admission and could I have it in writing.

they didn't want to write it down unsurprisingly

spent another 2 hrs with some lovey phone apple people who tried to help but could not and then I was passed to a senior support master who took all the details, got me to email stuff as well and is getting it to the engineers to look at so fingers crossed

I have a £10 hdcp stripper coming from amazon and will let you know how that test goes

my gut tells me its a hdcp issue as it even occurs when all the security is turned off on the t2

nice one

bob

Hey Bob, saw your reply and had to sign up...and thank you Drop for starting the post...

I have a 2018 MBP with 560x inside and I am having the same issue as you are. I am in the live entertainment industry as a video engineer and I plug my MBP into switchers all the time and have experienced this every three second stutter. I have been in contact with Analog Way which is one of the switchers that I commonly use, and they told me it's possibly a HDCP issue. I spent an hour with an Apple Senior Advisor over the phone for about an hour going through numerous steps.

What I found is that with HDCP enabled in the switcher, my MBP does not stutter but I can't get a picture from my MBP. But with HDCP turned off (which is what you normally do to get a picture and bypass HDCP) I can get a picture but my MBP stutters every three seconds.

This problem exists for the Analog Way switcher and also a Roland Switcher as well and it doesn't matter what adapter or cable you use and doesn't change when you restart. I've tried everything and even the Senior Advisor is puzzled.

Me and the Senior Advisor also think that it may be a T2 Chip problem as well. I have downgraded to High Sierra and have yet to test it again with a video switcher to see if it is in fact Mojave that may be causing it (Apple told me it can't be done because my MBP was supposed to be shipped with Mojave but there was a way. I have also called a friend that owns a 2018 MBP as well and he is still on High Sierra with no issues.

I did in fact find a work around when I was still in Mojave. I used a video converter like the cheap Monoprice HDMI to SDI converters and the problem went away. It may even work with an HDMI splitter that bypasses HDCP.

I encourage anyone that has this issue to call apple and report it to get a fix going. It is definitely hurting us professionals that use high end displays and video switchers

Hope this supplied enough information. I will regularly check this thread to help anyone out.
[doublepost=1561050351][/doublepost]

Did the problem go away when going into the decimator first?

 

[darenfoh]

hey mr d

glad im not going crazy, im running my show on my mbp retina late 2015 and the £4k 2018 mbp is benched until this issue gets fixed

decimator definitely does not strip hdcp, I get the same problem going hdmi > decimator > sdi

the lag even happens when I plug only my hdmi detective with hd resolutions programmed into it.

I spent 2 hours in our local store demonstrating it with it directly plugged into a lovely small hd monitor via hdmi with problem still persistent

they could not help me at all and suggested I try installing high Sierra myself as they were not authorised to do it. I have found it impossible on my model of mbp to do that, on my own that is

they did tell me that if they plugged into their monitors at resolutions of their choosing they would see the problem as mine as im doing something that the computer was not designed to do..... I did tell them that suggesting the 2018 was not capable of plugging into professional broadcast equipment that was a huge admission and could I have it in writing.

they didn't want to write it down unsurprisingly

spent another 2 hrs with some lovey phone apple people who tried to help but could not and then I was passed to a senior support master who took all the details, got me to email stuff as well and is getting it to the engineers to look at so fingers crossed

I have a £10 hdcp stripper coming from amazon and will let you know how that test goes

my gut tells me its a hdcp issue as it even occurs when all the security is turned off on the t2

nice one

bob

Yeah you're definitely having the same issue as me and tried all of the ways too. I was able to get my 2018 MBP downgraded to High Sierra and plugged it into a video switcher a couple of days ago and the issue is not there anymore. I'm pretty sure I didn't have an issue on 10.14.1. Would be ideal if you had 10.14.1 and just downgrade to that.

From what you have gone through it's 100% a HDCP issue and it is happening in Mojave. Have you tried it with the hcdp stripper yet?

 

[masondoesthis]

Update:

I took the MBP in to the Mac store and they replaced the logic board/ GPU as well as the fingerprint scanner button. I got it back to my work, installed a fresh copy of the OS and it worked! Sort of! For a minute! At first, the hitching was about every six seconds (maybe six and a half, I didn't measure, but it was consistent and the same interval), then I tried unplugging the monitors/ Decimators, plugging them back in, sleeping it, etc. (steps that had never had any effect previously) and eventually I was playing videos with no hitching on all my displays! It was great. So, thinking that it had turned out to be a hardware issue after all and that the new parts had fixed it, I restored from my earlier backup and presto, the 3.15 second hitch was back. "Okay, well, that narrows it down," I thought. So, I wiped the drive again, believing that it must be caused by some application I had installed, and reinstalled a new fresh copy of the OS and the problem still persisted!

Brand new again, but now with the OLD PROBLEM! How? It's almost as if the copy of the OS that they installed on my machine does not have/ cause this issue, but the copy that I installed on my own does.

IE, it can't be some application that I had on it. Booted into safe mode and found that the hitching does not present itself then. Interesting.

Eventually I tried plugging my system into two cheap hdmi splitters and plugging those into the Decimators. NO HITCHING!

I repeat, if you are having this problem, plug your hdmi into an hdmi splitter. This "shouldn't" do anything, but what it does do is strip the HDCP which must be the culprit somehow. I am highly annoyed, but I got it to work, so I am also happy and grateful for this continued conversation that led me to a fix.

APPLE! Please look into this issue. It is an OS problem and it is torture to the "Pros" you are marketing to. Earlier versions do not have this problem. Your user base has done much of the QA for you. Please fix it.

 

[darenfoh]

Update:

I took the MBP in to the Mac store and they replaced the logic board/ GPU as well as the fingerprint scanner button. I got it back to my work, installed a fresh copy of the OS and it worked! Sort of! For a minute! At first, the hitching was about every six seconds (maybe six and a half, I didn't measure, but it was consistent and the same interval), then I tried unplugging the monitors/ Decimators, plugging them back in, sleeping it, etc. (steps that had never had any effect previously) and eventually I was playing videos with no hitching on all my displays! It was great. So, thinking that it had turned out to be a hardware issue after all and that the new parts had fixed it, I restored from my earlier backup and presto, the 3.15 second hitch was back. "Okay, well, that narrows it down," I thought. So, I wiped the drive again, believing that it must be caused by some application I had installed, and reinstalled a new fresh copy of the OS and the problem still persisted!

Brand new again, but now with the OLD PROBLEM! How? It's almost as if the copy of the OS that they installed on my machine does not have/ cause this issue, but the copy that I installed on my own does.

IE, it can't be some application that I had on it. Booted into safe mode and found that the hitching does not present itself then. Interesting.

Eventually I tried plugging my system into two cheap hdmi splitters and plugging those into the Decimators. NO HITCHING!

I repeat, if you are having this problem, plug your hdmi into an hdmi splitter. This "shouldn't" do anything, but what it does do is strip the HDCP which must be the culprit somehow. I am highly annoyed, but I got it to work, so I am also happy and grateful for this continued conversation that led me to a fix.

APPLE! Please look into this issue. It is an OS problem and it is torture to the "Pros" you are marketing to. Earlier versions do not have this problem. Your user base has done much of the QA for you. Please fix it.

What version are you running? 10.14.5?

 

[masondoesthis]

What version are you running? 10.14.5?

Yes.

 

[darenfoh]

Yes.

Yeah that's when I first experienced it was 10.14.5 but it may have been there since 10.14.3. I downgraded to High Sierra and the problem went away. Definitely a Mojave problem.

 

[bobsbobs]

Yeah you're definitely having the same issue as me and tried all of the ways too. I was able to get my 2018 MBP downgraded to High Sierra and plugged it into a video switcher a couple of days ago and the issue is not there anymore. I'm pretty sure I didn't have an issue on 10.14.1. Would be ideal if you had 10.14.1 and just downgrade to that.

From what you have gone through it's 100% a HDCP issue and it is happening in Mojave. Have you tried it with the hcdp stripper yet?

so stripper works! stupid hdcp! re installed the show build of the laptop and tested today, no more regular frame drops.

I have let the apple dude who is looking into it know and await his response

much love to all the "plugging in Macs to pro video gear" crew

bob

 

[keithbgafn]

I spent months getting the "UPDATE is available" message that I would put off because we were on tour, once the leg of tour was over I said what the heck and updated.......... now I'm in a world of hurt video is lagging like crazy, although it starts off the day ok, by show time its crazy, so I think it may be a heat thing also. I will see if I can remove HDCP from the signal path and see if that works tomorrow at the next show.

 

[bobsbobs]

I spent months getting the "UPDATE is available" message that I would put off because we were on tour, once the leg of tour was over I said what the heck and updated.......... now I'm in a world of hurt video is lagging like crazy, although it starts off the day ok, by show time its crazy, so I think it may be a heat thing also. I will see if I can remove HDCP from the signal path and see if that works tomorrow at the next show.

try the hdcp stripper and invest in a stand with fans in it, its a must for uk summer festivals

 

[keithbgafn]

yes my 2018 MBP w/
Radeon Pro 555 always ran hot, so I have a stand already, and i'm already on amazon now looking to get one shipped tomorrow before my Glastonbury show.