iMac 27 inch 2020 - Screen Glitch (Random Lines Appear on Screen)

I’m thinking of returning for the i7 and standard glass to save the money since if it’s not quiet I would want the Apple Silicon version anyway. Maybe I should make a video on this. Might get some views lol.

I was considering the same. Was gonna return my i9 5700XT and get an i7 5700.

But despite what most of the reviewers are saying, I realised I will be actually able to utilise the plus 2 cores since I'm compiling in Xcode often, need perf bursts for multitasks and also running VMs regularly.

Not decided about 5700XT vs 5700 yet though. Have just bought a headless "dummy" hdmi plug which I'm gonna connect now to simulate a second screen being connected and if the glitching issues won't manifest themselves, I'll keep mine as is.

Got by the end of next week to decided if I'm keeping it

This is just a wild guess, but I'm going to bet the presence of a 5700 XT is going to increase fan noise over the 13 dB in that first link for a 2020 model with a 3.8 GHz i7 and the 5500 XT. Even for viewing a Web page. Ditto for the 10-core i9, even if its base clock rate is 0.2 GHz lower than the i7's. By how much, we'll have to wait for someone with really good noise measurement equipment and a soundproofed lab to tell us.

How I understand it, the fan noise difference between i7 vs i9 and 5700XT vs lower gpu, would be mainly (only?) in the way how often, how fast and for how long they ramp up the fans. The diff would be mostly noticeable in high temperatures, right?

What I'm saying is, that it's not the loudness of the fan that bothers me, but the "shape of the sound". Ie having a lower temperature setup won't resolve my personal problem with the sound of the fan while in idle state. My CPU is now 43C, ambient 36C and fan RPM 1198, nothing, literally nothing's running and I can hear the fan anyway.

Happy to be proven wrong of course. But you're right, we'd need a measured acoustic test, otherwise all these are only subjective interpretations and guesses, including mine.

Take a look at Activity Monitor and say again whether you think "literally nothing is running" when you don't see any user-facing apps with windows. On a modern OS, there are literally dozens of processes running in background. They may not be chewing up CPU or memory at any given time, but something is, even if it's only the logging services

It is the point when you state something that's patently absurd.... dude.

If meant to say you were simply comparing the two similar machines under like circumstances, you should have said it. are they similar? Does you 2019 machine have a high-end graphics card (for its time)?

FWIW, which may be nothing, your ambient temperature is a lot higher than the airco'ed labs in which Apple tested the noise levels. Most US workplaces are kept at 25 C or cooler. Even the more environmentally conscience set their thermostats at ~ 26 or 27 C.

But both your evidence and others here suggest that the sound spectrum (power as a function of frequency) is different in the 2020 model from previous ones, whether because of the absence of the HDD mounting hardware or some other reason.

Hi, I am reporting back that the line is back. It was gone for a solid week. It seems like resetting the SMC and NVRAM is only a temporary fix.

Also, I think Apple Insider wrote my way into one of their articles, so if they see this update they can declare this way is of no use.

I am too deep into customizing my softwares now to return it and wait another 2 weeks for it to come, so I am begging apple to come up with a fix.

I was having the exact same issue with my 2020 iMac 27".. I had order the Fully loaded iMac But i did only 4TB SSD and 5700 XT 16 gpu and even during a clean install/setup it was doing it during that too. When i tried to take a screen recording via the computer itself it came back with clean video, but recording from an iPhone on slow motion recording i caught it..

I sent mine back and a new one is on the way, hoping the new one doesn't have the same issue. that would suck...

But i am so glad to see i am not the only one with that issue, but not sure if this makes me feel better or not now lol

Tom

lol im with you, i thought the exact same thing... I was tired when i was setting it up and thought maybe it was just me.. After setting it up i noticed the line glitch which was really just random at best.. But i would have a quick time screen recording going at the same time as an external camera recording the screen. The Screen Recording from Quick time showed a perfect screen everything time, while the external camera caught all the glitches..

I order the 10 core 5700XT 16 GB GPU 10GB Eithernet, 4TB SSD (8 GB Memory - not paying 2600$ (which is absurd...) for128 gb when i can get it cheaper elsewhere

But anyhow My replacement comes in on the 16th of September, if it still has the issue i may send it back for a refund at that point and then just wait to see what is causing the issue.

Hope the new unit is fine.

That's very interesting! According to Apple's technical specification page the sound level of the iMac 2020 at idle is 13 dB. According to comparable sound level charts, this is equivalent to normal breathing (10 dB) and yet more quieter than whispering from 5 feet away (20 dB). My general reaction is that I'd be a little disappointed if I heard the fans when doing non-intensive tasks such as emailing and web browsing. My MacBook Pro Retina 13" Early 2015 is silent doing those tasks! But at 13 dB, I'd be reasonably happy with that - as I work in a quiet office and don't like a lot of background noise. For those of you that own the iMac 2020 can you please confirm... is "equivalent to normal breathing" a realistic comparable sound level that is being experienced?

I'm wondering too if this dB rating takes into account any contributing noise from the Radeon Pro graphics options. Surely the 5700XT is louder than the 5700 for instance!?

Also, I've read some owners reporting that the iMac 2019 is quieter than the iMac 2020 at idle, but yet it's rated slightly higher at 16 dB at idle on Apple's tech spec page. I would think removing the mechanical drive and leaving a lot of empty space (presumably creating better cooling) would cause the iMac 2020 to be quieter?

For those of you that own the iMac 2020 can you please confirm... is "equivalent to normal breathing" a realistic comparable sound level that is being experienced?

The sound level of breathing with open mouth I'd say, yea. That's how my top spec iMac 2020 sounds when idle. (As opposed to top spec iMac 2019 which was dead silent when idle.)

I would think removing the mechanical drive and leaving a lot of empty space (presumably creating better cooling) would cause the iMac 2020 to be quieter?

Leaving a lot of empty space just makes it sound more like as if coming from a tin can. (As opposed to the 2019 model, which sounds more dampened down.)

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Overall, the fan noise while idle is not that bad for me personally, since I'm not recording pro audio and am on headphones most of the time anyway, so can't hear it.

I'm more bothered by the graphical glitches, GPU crashes in games and BT keyboard lag in certain apps :/

Same issue on my new iMac 27 2020. Has anyone been able to resolve this issue with Apple support? Would love to learn how Apple can resolve this technical/software/hardware issue for so many consumers/users. If the Apple Stores were open for business, I would return my iMac system for a new one. Would love to hear how others are dealing with this issue good or bad. Thank you

"Surely the 5700XT is louder than the 5700 for instance!?"

Unlike in the 2019 Mac Pro and PCs with PCIe slots, the graphics here is just a chip, apparently soldered to the motherboard. (See iFixit's less than elaborate teardown.) There's only one (fairly large) fan in the iMac 27, and any internal noise, now that HDDs are a thing of the past, is noise from that fan.

Presumably, yes, the 5700 XT (40 compute units) generates more heat than the 5700 (36 units), and thus requires more cooling.

Thanks for sharing. I returned my unit and will not order a new one before someone can confirm that

the issue(s) have been addressed - preferable via a software update. I still wonder if the white line flashes and my full system crashes are/were related.

Boy, this is so disappointing. I was getting close to ordering one of these, but I think I will wait a few months until they address this. It seems to be a widespread issue. For all that $$$ (and all the $$$$$$$$ that the company has available) this seems like a major fail.