iMac slows down after Big Sur inst… | Apple Developer Forums

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Hello!
I downloaded the macOS Big Sur image on MacBook Pro, then installed, everything works fine.
I started downloading the macOS image on iMac, but at the end I constantly got a loading error. Then I install image on USB from MacBook and installed it on iMac. After installation, iMac began to slow down, for example, it opens a folder in a few seconds or or launches the browser in 10 seconds.
With what it can be connected?

iMac (Retina 4K, 21.5-inch, 2019)
Serial Number C02Z1085JWDX

macOS

58k

Posted by

Kirill1104

Reply

Hi! I have an iMac27" late 2014 and after I installed Big Sur 11.4 my system with 32GB of RAM and this (shit!) Fusion drive system is come really really slow... until to 15/20 min to lanch an app!!! And I think with the next versione of macOS 12.x it will be definitly "dead" for Apple... so I decide to remove macOS at all and try to install Ubuntu or other GNU/Linux based distro. I am an Apple user from 1995 and this make my really un-happy... No good solution I have found to solve this issue, the only one seams to be just only change internal drive with a full SSD disk (pity this means 3/400 Euros...)

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FScarfato
I have 27” imac late 2014 i7 cuad qore turbo ram 32g with frigin fusion too. 3tb. The best part is only 128g is ssd. Balance is hdd.definitely not obsolete yet with fast moving tech. Just like cr7 n messi. Still relevant. anyway. Same prob. Mac os big sur slow. Apple consider our mac is vintage. My solution, i drop fusion. Keep the 128 ssd bought new 500g ssd. Partitioned. Then reformat to mac os catalina. This is the way! This is the way p/s convert hdd to externals. N set up NAS. Network attached storage. Wireless. But lagging when accessed

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Hilmi21_zul
Clearly Apple has gone to the dark side with a nasty update. You know they know (if we could only get an Apple employee on the OS dev team to speak LOL). They made an update that's good for some models (and their profit margins), but destroyed perfectly good computers with a dirty move. I am furious with this I'm not buying another mac ever, because somewhere in the near future I'll face the same putrid ***** because of another lame thing they do for their profits. Windows/bootcamp are my future

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dreganism

Replies

Hello!

Same here MacBook Pro everything works fine. iMac late 2015 1TB Fusion Drive is very slow. Startup takes very long too.

Posted by

Jodec

Same with my iMac, startup is very slow and apps lunch much slower after installing Big Sur.
It's probably something with fusion drive and how Big Sur use it. Hope they will fix it :/

Posted by

filip.petkovic

Same here on 2019 iMac, tried on Fusion Drive and also external, same results, extremely slow startup and app opening. At this point not usable at all.

Posted by

twmuse

Same experience. Even I am on quite old comp (iMac (Retina 5K, 27-inch, Late 2015), its still 60-70% slower then on last Catalina version. Startup, App loading. Safari is the worst, takes about 10-15sec to start loading pages - but before it says I am not connected to the internet. Same on my MBP 2018.

Posted by

mp_72

Hello,

Yesterday I installed the official Big Sur release on my iMac (2020, 5k 3,8 ghz, 2 months old) and I see a huge slow down in performance. All the problems mentioned above. Also when I input text in Safari or Spotlight the letters come too late after I press the keyboard button. There is a huge lag in writing, also opening images or websites!

Posted by

bpprodanov

I'm having the exact same issue as everyone else on this thread. Startup is very slow and choppy. It also takes about 5 minutes to load a project in Logic Pro X using minimal resources. It's almost unusable. Hoping they can fix this soon.

Posted by

anthonyhoward

Hello, I am on a iMac 27" 2019, is really slow, it should be a joke, but even write this message took me around 40 to 70s, cause it lags with just writing on an input.

Posted by

TeraBit

iMac 2015 with Fusion drive: after installing Big Sur 11.0.1, startup is painfully slow. At least three to four times slower than 10.15. It seems as if it is reading everything from the rotating HDD instead of the SDD portion.
After boot is complete, apps are then pretty snap and speed is back to normal.

Posted by

Enryfox

Same here with my iMac, especially the dock, it animate very slow, it locks too much, even when blur is off.

Posted by

PremedPablo

Yes, exactly the same performance issue. I have an iMac 27" Late 2017, and the boot went smoothly UNTIL I upgraded to Big Sur. Big Sur has made my computer boot extremely slow. Apps also take lots of time to load.

Posted by

alejandrosejas

I have an iMac 27" Late 2017 too. Since I installed Big Sur, it takes ages to boot and load any application... Until last week my computer run smoothly.

We all seem to have the same issue, so it's most probable that Apple will make an effort to find the source of this problem. Let's trust them as always.

Posted by

mikeru

Same here guys.
Just installed official Big Sur update yesterday on my Macbook Pro 16" 2019 and the lag on typing is just unbearable.
I've disabled that accented character popup, changed my key repeat to the max but still, very noticeable and annoying lag when typing.
Anyone found a solution yet?

Posted by

lenineto

hello :) I have installed big sur on my iMac, and it became super laggy. I started the installation on the mac mini and fortunately it didn't have time to complete so I cancelled it. in my experience, installing Big Sur now is a BAD IDEA.

Posted by

Papanoos

Hello! I have 2019 iMac 27 with 24GB ram, and i have upgraded to macOS Bigsur yesterday and it's slowed my mac totally! It need about 10 years to startup system, about 4 seconds to startup safari. But in safari, when browsing, everything is smooth and super fast like usual. Just think there will be another update very soon to fix this problems with starting up.

Posted by

simad4sx

Hello! I have 2019 iMac 27 with 16GB ram. take very long to startup, after the long startup, the overall speed are ok.

Posted by

tnctan

I upgraded to the macOS Big Sur on iMac 2017 (Retina5K 27 inch 3.8Ghz Quad Core Intel Core i5 32GbRam). After installation, iMac began to slow down. Safari takes minutes to open the first page after which it now fails to open anything, this has been a total failure. Please let me know what to do as I have been using Macs since the early 90's - My business is in media and this has impacted my business significantly.

I don't keep files on my iMac, (music and pics only) they are all stored on separate external drives

I look forward to your assistance, hopefully quickly.

Thank you

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AnthonyFox56
Are your hard drives also very VERY slow at adding and removing files? I think I've been experiencing the same issues.

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SurfingOregon424
I installed Big Sur as soon as it came out and it worked find on my 2014 late model 27 inch iMac with 16 gig memory/iCore 7 processor and in the last couple of weeks it started slowing down with the dreaded spinning color wheel. Finally today it just froze up. I switched to recovery mode and had to erase the 120 SDD drive and install Yosemite and was successful. Then I tried to upgrade to Big Sur and that was a disaster. So I just erased it again and am re-installing Yosemite. Think I will just keep Yosemite going for a while. My backup drive with Time Machine isn’t recognized, so it looks like a total disaster. We know that Yosemite works on this old iMac so I will just keep it going for a while till if figure out something.

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