MacBook Pro (Retina 15-inch Mid 2015) Intel Iris Pro Graphics screen glitching

[j3sse]

I wanted to see if I can get some sort of consensus on this issue:

When running more than a few graphic-intensive applications at the same time, and pushing both an external 4k screen and the built-in retina I'll notice sporadic glitching on the retina screen. It usually lasts only a few seconds, and only seems to happen on the retina screen.

I'm tempted to chalk this up to the underpowered integrated GPU just bonking from being overtaxed, but I figured I'd post the images here and see if other people have experienced the same thing and it's perfectly normal, OR if people feel this potentially points to an eventual failure.

Specs:

MacBook Pro (Retina 15-inch Mid 2015)
2.2GHz quad-core Intel Core i7
16GB of memory
512 GB SSD
Intel Iris Pro Graphics *only*
macOS 10.14 Mojave

Thanks All

 

[chscag]

First, have you tried swapping out the cable/adapter between your MBP and the 4K monitor?

I doubt if the Iris Pro graphics chipset is wonky or intermittent as it's part of the CPU setup. I have never heard of one going bad although I suppose it's possible. You could well be right about taxing the GPU, however, with 16GB of on board memory the Iris Pro should allocate enough for itself. I'm not sure how much memory the Iris Pro can use from the main memory but you should be able to find that out from the specs.

 

[ferrarr]

What are the display settings for both displays? Here are the specs for your MBP, MacBook Pro "Core i7" 2.2 15" Mid-2015 (IG) Specs (Retina Mid-2015 15", MJLQ2LL/A, MacBookPro11,4, A1398, 2909): EveryMac.com. It comes with 1.5gb VRAM. Also, how are you connecting to the 4k tv Thunderbolt or HDMI?

 

[badshoehabit]

Your graphics card is kaput. Been there, done that, got the replacement for my 2011 model which was subject to a Repair Extension Program.

Mine looked like this:

 

[iggibar]

Easy way to diagnose this issue:

Run MBP in safe mode. See what you get.
Run MBP with an external monitor. If it's a problem with the integrated Iris graphics, you will have the same problem on the external.
If problem only shows on the MBP, and NEVER on the external, your screen cable is is bad.
-this could be caused by open/closing wear, connections going bad, liquid spill, or high moisture/humidity environments.

What I would do is try unplugging the screen connector, and plug it back in.. The individual connections or TINY, so you better be 100% sure you have the male connector going into the female sire perfect or it can easily short on the left side of the connection.

 

[jasongoldworthy]

well so far iggibar is the only one who read the post correctly


and as the OP has said its not happening on his 4K display just the integrated display


so as iggibar has said it could be a bad display cable between both the screen and the logic board.


it could also be the display panel itself going bad.

 

[chscag]

so as iggibar has said it could be a bad display cable between both the screen and the logic board.

However, since the OP has not gotten back to us, we won't know.

 

[j3sse]

Well - I figured I'd see how many twists and turns the conversation took

With that said:

1. I did try running the machine in Safe Mode briefly, but quickly realized it wasn't going to work. Doing so makes it difficult to mimic the same conditions that bring about the glitching in the first place. It typically happens when I'm working in multiple GPU-intensive applications - not just when I have them all open. Starting in safe mode seems to hamstring those same applications - so I can't really work in them.

2. I question whether the built-in screen's display cable is the culprit as it doesn't happen when I am using it as my only monitor. My feeling is that if a bad cable was the cause, I'd see it no matter the circumstances.

3. I always use the thunderbolt/mini displayport to drive the monitor - and to date have used two different cables. I didn't bother trying a third cable as the glitching has never appeared on the 4k monitor.

I honestly was hoping to get a weigh-in on my hypothesis that this the result of an underpowered integrated GPU - or more importantly, validation that others have experienced the same thing (with or without it being an all-out failure). I have yet to look up the specs to address whether the 16 GB of ram is enough to bridge the gap.

Thanks to all who have weighed in so far.

 

[ferrarr]

What are the settings for both displays? In System Preferences > Displays

 

[Raz0rEdge]

Since the integrated graphics chip shares the system RAM and you are working with GPU-intensive apps which might also be using a lot of memory, you might be just starving the GPU. If things behave perfectly fine with no active load on the GPUs, then it is likely not a cabling issue.

Once the glitch happens, is your only recourse of getting back into business powering down the machine?

Can you open up a Terminal window and then run the following command before running whatever sequence of things that causes the issue?

$ cd ~/Documents
$ while 1; do mem=`top -l 1 | grep PhysMem`; d=`date`; echo "$d - $mem" >> mem.log; sleep 5; done

You can kill this script at any time by hitting CTRL+c or when the glitch happens by powering down your computer.

Now in your Documents folder (you can open this up in Finder), you'll have a mem.log file that contain information like this:

Mon Aug 19 08:56:21 EDT 2019 - PhysMem: 14G used (3578M wired), 1954M unused.
Mon Aug 19 08:56:27 EDT 2019 - PhysMem: 14G used (3602M wired), 1911M unused.
Mon Aug 19 08:56:33 EDT 2019 - PhysMem: 14G used (3594M wired), 1919M unused.
Mon Aug 19 08:56:38 EDT 2019 - PhysMem: 14G used (3555M wired), 1905M unused.
Mon Aug 19 08:56:44 EDT 2019 - PhysMem: 14G used (3583M wired), 1920M unused.
Mon Aug 19 08:56:50 EDT 2019 - PhysMem: 14G used (3596M wired), 1923M unused.

On my 16GB MBP, I have 3.5GB that is wired and cannot be replaced and about 2GB free for use. The Used isn't as useful. Once your unused number starts to dwindle down, you start swapping to disk. However, the things that are wired are not swappable.

What you are looking to see if your unused memory gets down to 0 or very close to 0 and your wired starts jumping high.

Report back on what you see and we can go from there.

 

[j3sse]

Once the glitch happens, is your only recourse of getting back into business powering down the machine?

Nope, the glitching only lasts a few seconds.

Can you open up a Terminal window and then run the following command before running whatever sequence of things that causes the issue?

$ cd ~/Documents
$ while 1; do mem=`top -l 1 | grep PhysMem`; d=`date`; echo "$d - $mem" >> mem.log; sleep 5; done

...Report back on what you see and we can go from there.

Will do. Since it appears sporadically, can I just let this script run for awhile until the glitch rears its ugly head?

Thanks,

j3sse

 

[j3sse]

What are the settings for both displays? In System Preferences > Displays

Built-in retina screen: 1920x1200 @ 144 dpi (3840x2400?)
External [Samsung U28E850]: 3360x1890 @144 dpi (6720x3780?)

...and, potentially answering my question is this line of text in the resolution controls:

"Using a scaled resolution may affect performance"

So... yeah, this could be it as both of those settings are scaled as sh*t. Which again, leads me to believe I'm hitting the upper limit of the GPU's abilities. If that is the case, my guess is setting both monitors to their default resolutions will probably go a long way to addressing it.

Is it then too much of a leap to say that it's likely a dedicated GPU would have been able to handle this?

 

[Raz0rEdge]

Nope, the glitching only lasts a few seconds.



Will do. Since it appears sporadically, can I just let this script run for awhile until the glitch rears its ugly head?

Thanks,

j3sse

You can run the script for as long as you want. The amount of data being stored in the file is small enough so it shouldn't grow like crazy, but you might want to kill the script if you aren't going to be using your computer for an extended period of time to avoid having the file become very large unnecessarily.

 

[ferrarr]

From what I read, the external can not be supported at that resolution "External [Samsung U28E850]: 3360x1890 @144 dpi (6720x3780?)", have you tried lowering it? Maybe the card can handle both at lower resolutions?

 

[j3sse]

Interesting - well, I’ll see what the result is if i change the resolution to a lower setting. Do you recall where you read about this limitation?

Thanks for looking into this, I appreciate your time.

 

[ferrarr]

I get all my information from everymac.com, Mac Specs, Prices, Answers and Comparison: EveryMac.com, Est. 1996. Here's the page for your MBP, MacBook Pro "Core i7" 2.2 15" Mid-2015 (IG) Specs (Retina Mid-2015 15", MJLQ2LL/A, MacBookPro11,4, A1398, 2909): EveryMac.com. Look at the "Displays" information. Also, there is this, MacBook Pro (Retina, 15-inch, Mid 2015) - Technical Specifications.

 

[pm-r]

Interesting - well, I’ll see what the result is if i change the resolution to a lower setting.

I have no idea if it might help or not, but I wonder if SwitchResX.app could poosibly help with your setup and problem???:
SwitchResX - The Most Versatile Tool For Controlling Screen Resolutions On Your Mac

Just a bit of a crazy thought... but one never knows...



- Patrick
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