iMac 2020, 5700XT - graphical glitch?

[kkh]

Had a lengthy and thorough phone conversation with Apple today. They asked for a bunch of details and I offered up all the information as to what I am personally experiencing and also what we have collectively experienced and documented here. I will be sending videos and logs to them shortly. They sound determined to get to the bottom of this.

 

[Conradiminja]

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[anthony13]

To summarize my experience, I have the white line glitch, and yesterday started noticing the upper left corner of certain windows have a small glitch where it turns black like it’s filling out the rounded corner. 5700xt. All on my screen (no external).

 

[CE3]

I've found a lot of posts of MBP 16" users that have a horizontal white line glitch on the external display, both 5300m and 5500m users. My MBP didn't have any flicker/ horizontal line glitch for 6 months and started doing it after upgrading to 10.15.6 so my guess is that its something with the t2 chip / 5xxx series GPU's that cause this.

The white horizontal lines look like this on my external display only (the horizontal flicker is a solid white line but my iPhone didn't capture it completely in slow motion since its so fast)

Here I have a stackexchange discussion from 2018 discussing it:https://apple.stackexchange.com/questions/306674/flickering-white-lines
My own post on ifixit: https://www.ifixit.com/Answers/View/649664/White+line+flash-flicker+on+external+display

The only way I've found so far that stops the glitching completely (at least it seems so) is to run on a lower resolution on the external display (2048x1152 instead of 2560x1440) and I've read a few replies in the thread saying the same solution works for 5700XT users where a lower resolution made the glitching stop completely on the built in display. Also switching to Big Sur or Windows seems to stop the glitching completely (haven't tested it myself yet) so its 100% driver or 10.15.16 related.

Hopefully I don't have the glitch with my new iMac 5700XT, but this does seem to be more likely a software bug than a hardware issue.

2048 x 1152 has always been my default display resolution for text, icon, and window sizes. FYI: upscaling doesn't reduce video and photo resolutions.

 

[torifile]

I've found a lot of posts of MBP 16" users that have a horizontal white line glitch on the external display, both 5300m and 5500m users. My MBP didn't have any flicker/ horizontal line glitch for 6 months and started doing it after upgrading to 10.15.6 so my guess is that its something with the t2 chip / 5xxx series GPU's that cause this.

The white horizontal lines look like this on my external display only (the horizontal flicker is a solid white line but my iPhone didn't capture it completely in slow motion since its so fast)

Here I have a stackexchange discussion from 2018 discussing it:https://apple.stackexchange.com/questions/306674/flickering-white-lines
My own post on ifixit: https://www.ifixit.com/Answers/View/649664/White+line+flash-flicker+on+external+display

The only way I've found so far that stops the glitching completely (at least it seems so) is to run on a lower resolution on the external display (2048x1152 instead of 2560x1440) and I've read a few replies in the thread saying the same solution works for 5700XT users where a lower resolution made the glitching stop completely on the built in display. Also switching to Big Sur or Windows seems to stop the glitching completely (haven't tested it myself yet) so its 100% driver or 10.15.16 related.

And thus it’s a different problem. It’s a different card, machine and use scenario. The only similarity is the white line.

 

[ErikGrim]

Also switching to Big Sur or Windows seems to stop the glitching completely (haven't tested it myself yet) so its 100% driver or 10.15.16 related.

How are you switching to Big Sur on a 2020 iMac? Beta 6 isn't out yet?

 

[joevt]

If 2048x1152 doesn't have a problem but 2560x1440 does, then maybe try adding a 5088x2862 scaled resolution (gives a 2544x1431 HiDPI resolution).

 

[Conradiminja]

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[highlypaid]

I got my 2020 iMac Thursday night. It's as fast as expected and gorgeous. Last night I thought I saw, out of the corner of my eye, a horizontal white line flash mid-way up the screen. It was really fleeting and I thought I was just seeing things. This morning, I saw the same thing. The computer isn't running hot or anything. iStat Menus has all the cores untaxed. I recall having this same problem with my MBP 13" (2019) with an earlier version of macOS (I can't remember if it was a late Mojave build or an early Catalina) and it was cleared up with a software update.

Anyone else noticing flashes of graphical issues?

iMac 20,2
3.6 ghz, 10 core
5700XT
32 gig OWC RAM (OEM RAM has been removed)
2TB SSD

I saw it the first time I booted up, never again so far.

 

[GreenDice]

I've found a lot of posts of MBP 16" users that have a horizontal white line glitch on the external display, both 5300m and 5500m users. My MBP didn't have any flicker/ horizontal line glitch for 6 months and started doing it after upgrading to 10.15.6 so my guess is that its something with the t2 chip / 5xxx series GPU's that cause this.

so its 100% driver or 10.15.16 related.

This sounds like good news if it is true. The 5700XT is about 50/50 in the poll now. If it is really software problem, my theory is that problem exists 100% but 50% of people have not caught the flash in the act yet. May be?

 

[torifile]

It's still relevant to discuss this since both machines uses the RDNA Navi architecture graphics card. I've been in contact with users on macforums, stack exchange and ifixit with various machines that all had the RDNA Navi (5xxx series) GPU's: 5300m (MBP 16" ), 5500m (MBP 16"), 5600m (MBP 16"), 5300 (Imac 2020), 5500XT (Imac 2020), 5700XT (Imac 2020). All of these machines experienced the white line flickering / glitch problem since updating to 10.15.16.

If its something that affects more configurations and products than just the 5700xt, then in my opinion its relevant to include it and discuss it to find out as much information as possible to see what solutions work to minimise or eliminate the flickering for all users that experience the problem .

Currently: Running a lower resolution or a custom resolution seems to reduce to flickering or eliminate it completely for both MacBook Pro 16" and Imac 2020 users with the 5xxx cards.
I'm running my external display (D-GPU constantly enabled) 2500x1400 instead of 2560x1440 using SwitchResFX which is giving me promising results with no glitching in the last 4 hours or work.



Could have been more clear, MBP 16" users that had the white line glitch that tested Big Sur beta / Windows 10 haven't experienced any glitching. So its most likely MacOS drivers related. . Will be interesting to hear from more Imac 5700XT users when they test windows / Big Sur (when available) to see if the problem goes away by doing that.

You’re not even using a 2020 iMac. How you’re fixing your issue is irrelevant to the issues reported here.

It could be a more broad RDNA/Navi issue but I think you’re just confusing things. All those other machines are running intel processors too but you wouldn’t blame that, would you?There are no reported problems in the 5300/5500/5700 iMacs, at least in this thread. Where you are seeing that is beyond me. I think you’re just barking up the wrong tree.

This does NOT occur at default resolution with a secondary display. I’ve been literally staring at my screens for 30 hours this week with a secondary display connected and there hasn’t been a single instance of the flickering.

You are saying there is a problem with an external in those other machines. There is no reported problem, even at default resolution, when an external is connected on the iMac.

It may seem like I’m splitting hairs but specificity in troubleshooting is important and you are conflating and confusing the issue.

When you talk about how you fix your problem on your MBP, you are just making things hard to deal with for people who need to see how to fix their problems with the 2020 iMac.

 

[shywizard]

Had a lengthy and thorough phone conversation with Apple today. They asked for a bunch of details and I offered up all the information as to what I am personally experiencing and also what we have collectively experienced and documented here. I will be sending videos and logs to them shortly. They sound determined to get to the bottom of this.

Same here. Today I sent 2 log files to Apple so they can analyze my computer data while the white horizontal line glitch occurred. First log was a single flicker. The second was a double flicker. Hopefully they can figure this out.

 

[thiskiwicanfly]

After reading all the comments it seems to me to be a software related issue with MacOS Catalina particularly with examples given of the glitch occurring in a sort of logical way (on the outer edge of an active window) rather than blatently across the entire screen, and also no one is reporting it happening in Windows bootcamp either.

But I’m very nervous about this as I’ve just ordered the iMac 27” 2020 3.8GHz 8-core i7 with 5700XT graphics before hearing about this issue, and am hovering my finger above the cancel order button as I speak. Not sure what to do!

 

[torifile]

After reading all the comments it seems to me to be a software related issue with MacOS Catalina particularly with examples given of the glitch occurring in a sort of logical way (on the outer edge of an active window) rather than blatently across the entire screen, and also no one is reporting it happening in Windows bootcamp either.

But I’m very nervous about this as I’ve just ordered the iMac 27” 2020 3.8GHz 8-core i7 with 5700XT graphics before hearing about this issue, and am hovering my finger above the cancel order button as I speak. Not sure what to do!

Don’t worry about it. It’s almost certainly a software thing that will be fixed in short order. I wouldn’t cancel the order if the 5700xt is what you need/want.

 

[thiskiwicanfly]

Don’t worry about it. It’s almost certainly a software thing that will be fixed in short order. I wouldn’t cancel the order if the 5700xt is what you need/want.

I just cancelled my iMac 2020 i7 5700XT order as it has somehow dampened my excitement of getting a new iMac with the possibility of the glitch issue happening to me. It most probably is software related as you say but I’d rather wait until the issue has been identified by Apple and sorted. Interestingly I told Apple (Australia) about the issue and she told me it was the first time she’d heard about it.

 

[jamespb78]

If 2048x1152 doesn't have a problem but 2560x1440 does, then maybe try adding a 5088x2862 scaled resolution (gives a 2544x1431 HiDPI resolution).

Having never owned a 5K iMac, can someone tell me what resolution the 27" display normally runs at?

I would have assumed it would be at 5120 X 2880 as advertised by Apple. So isn't changing the resolution down to 2048 X 1152 a massive trade off?

 

[thiskiwicanfly]

Having never owned a 5K iMac, can someone tell me what resolution the 27" display normally runs at?

I would have assumed it would be at 5120 X 2880 as advertised by Apple. So isn't changing the resolution down to 2048 X 1152 a massive trade off?

Correct me if I’m wrong but it’s a scaled down resolution which means the original number of pixels on the 5K screen will be the same size, but things will occupy twice as many pixels in both dimensions, so all text elements for example will still look sharp and crisp, as well as bigger.

 

[ADGrant]

And thus it’s a different problem. It’s a different card, machine and use scenario. The only similarity is the white line.

Well that and the GPU architecture, operating system and video drivers.

 

[Conradiminja]

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[wilberforce]

Having never owned a 5K iMac, can someone tell me what resolution the 27" display normally runs at?

I would have assumed it would be at 5120 X 2880 as advertised by Apple. So isn't changing the resolution down to 2048 X 1152 a massive trade off?

The default scaling for the 5K iMac is 2X. See screenshot below. This means it maps a traditional (non-retina) 2560x1440 desktop to a 5120x2880 resolution screen.
The tradeoff in using a different scale factor, is that everything looks bigger ("Larger Text"), or smaller ("More Space"). The default scaling is usually the best balance for most people.
There is no noticeable resolution loss by using a different scale factor, that I can see, although Apple says: "Select “Default for display” to automatically use the best resolution for the display" and "Using a scaled resolution may affect performance."

 

[ADGrant]

At least now there are some videos about it. we might get it solved quicker

We are famous!

I agree with a lot of his comments except for the fan noise, my NAS is louder. I don't love the keyboard either but not a problem, I use a mechanical keyboard with Cherry MX switches.

 

[ADGrant]

So I just setup my iMac with the 5700XT today. I did see a white line flash twice while in the setup screen. After setup my Mac downloaded the latest updates and rebooted. I haven't seen any more white lines yet.

 

[ADGrant]

I'm discussing the issue in this thread but also with members of Stackexchange and Ifixit where there are users of the 5300/5500 Imacs and various MBP 16" configs that have contacted me (through PM) to troubleshoot and try coming up with a solution since they experience the exact same glitching that I described and other users in this thread show photos / videos of.

The issue is the same, white horizontal line, glitching / flickering for a fraction of a second. For most users it seems to be at the same area of the monitor of both Imacs and Macbook Pro's.

Personally I find your contribution to this thread to be very helpful. Are you saying that on other forums, owners of 2020 iMacs with GPUs other than the 5700XT have experienced the same issue?

 

[thiskiwicanfly]

So I just setup my iMac with the 5700XT today. I did see a white line flash twice while in the setup screen. After setup my Mac downloaded the latest updates and rebooted. I haven't seen any more white lines yet.

Please post a comment if you do see it again as I cancelled my iMac 5700XT order earlier as I just want to be sure it’s fixed in the latest updates before reordering.

 

[chill991]

So I just setup my iMac with the 5700XT today. I did see a white line flash twice while in the setup screen. After setup my Mac downloaded the latest updates and rebooted. I haven't seen any more white lines yet.

Same here, my iMac showed up today and while setting it up, I noticed the white line several times during setup. While using it tonight, I haven't seen anything.