iMac slows down after Big Sur installing

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
I have had upgraded 3 or 4 OS's since 2017 on my mac pro retina and loved each one of the upgrades.

Now this BIG SUR is BIG disaster. Not only has my mac become non sense but even the whole UI and logic of work arounds and clicks to execute a process doesn't make sense. some of the Main issues :

  • Boot up takes around 3- 4 mins compared to a min before, lets say on catalina or Mohave or previous versions

  • the apps take forever to open , if they open , the icons just keep bouncing, dunno what that is now .

  • Battery is draining like its no ones business , and weirdly enough , from 20% drops to 11 % then 1 % . amazing !

  • it took me around 3- 4 restarts and had to turnoff/on wifi several times to make it work, that is the new norm.

  • the fan keeps coming on and the computer stalls randomly , i mean this is a disaster, are you watching this steve ???


This is just a brief summary of whats happening , the UX mess up is a whole different conversation.

God Help #apple

I have a pretty new 2019 MacBook Pro and hardly anything saved on it, as far as memory goes, etc. Big Sur has SLOWED down my mabook pro A LOT ! While I like some of the features, like better iMessage, and mirroring iPhone stuff a bit more, i.e. control center, my safari runs AWFUL ever since I downloaded Big Sur and sometimes there are significant freezes in all functions of computer. So far, this is VERY dissatisfactory and also frustrating. I mean, my computer is relatively new.
I have a Mac Book Pro 2019. Fully maxed out. 2.4 GHz 8-Core Intel Core i9. SSD 2TB. Since Big Sur update there is a delay on EVERYTHING. Safari slower, Internet slower, programs slower, everything. I wish I wouldn't have updated it. I did many tips I found online and Clean My Mac software, nothing worked. Please resolve asap. Sad part is I love the new photos for desktop...ha what a lame trade off:-)
My MacBook Air 2015 since I got the new update is a totally disaster!!
Runs everything slow, always hot, very noisy and besides this the battery drain like hell.
This is VERY disappointing apple, please fix this!
if you have the macOS Catalina DO NOT INSTALL the bigSur
Updated to Big Sur yest. on 2015 model.
File system is very slow.
Files appear in folder after few seconds.
Deleted file appear in Trash after few seconds.
File copy is slow, file opening is slow.
What is the solution for this?
2018, $3000 Macbook Pro here. Since big sur update even key presses seem slow sometimes. WindowServer is always at 50% CPU usage or more, laptop is always hot and random out of memory errors are regular.

Next laptop will be Linux...
2017 macbook pro.
  1. GhZ dual core i5.

8 Gb RAM.

I am incredibly frustrated. Big Sur turned my computer into a brick compared to performance on catalina. I've been using a windows xp old comp that I have at work. It takes sometimes 10-15 seconds for finder to open. My slowdowns are system-wide. From browsers to messages. My god messages... Sometimes takes 20 seconds to open messages. I can't work like this.
Please fix.
I expected a windows PC to last 2-3 years and a Mac to last 5-7 years. Please fix this has been a nightmare.

Hey, same frustration here.
Yesterday I've bought an iMac 4K, 21.5-inch, 2019, with Big Sur. I've bought it because I thought it's a good idea to work on Mac to complete my maser thesis.. I made good experience with iPad Pro and thought I would experience the same productivity with an iMac
But Big Sur is Big Fail - it takes 10 to 20 seconds to just open small Apps like Notes..
The 1TB HDD ist non-stop(!) working.

Why is apple not immediately solving this Big Problem???
iMacPro 2017 10 Core 32GB 1TB SSD Not totally maxed out but It should not be this slow. Only Chrome, Activity Monitor, McAfee anti virus and 42 calc running down to 3.08 GB free. Slow as ****.... Also sorted the AM screen by memory usage and daemon has 243.08 GB and growing. Makes no sense was not like this in Catalina. Then like that the daemon wiped to zero and started growing again. Other than typing this message wasn't doing anything else :(
Same problem here, I have:

MacBook Air (MID-2013)
1,7 GHz Dual-Core Intel Core i7
8 GB 1600 MHz DDR3
Intel HD Graphics 5000 1536 MB

and in catalina OS works very well and fast, I have to downgrade it :(
I have a Mid 2015 MacBook Pro with 1TB SSD and the fan starts spinning a few minutes after booting, then the system crawls after about an hour of so, especially when left idle. What's frustrating is that the slowness always occurs, even if I don't open any apps.

MacBrick "Pro"
This is utterly insane--the drastic reduction in speed. I have learned a very valuable lesson with these updates. Wait a while. Wait a good long while. Hopefully Apple will announce they're looking into it and/or addressing the situation.
I feel that my MacBook Air (Intel 2020) became significantly slower with increased battery drain. Should we all sign the collective complaint or something?
I also have a Retina 4K, 21.5-inch 2017 and am extremely frustrated with how slow this is running. The lack of speed has become very problematic! Slow to wake up and load apps, black screen, etc. I never had this problem with previous operating systems. Please fix soon!
iMac (Retina 5K, 27-inch, 2019)
3 GHz 6-Core Intel Core i5
48 GB 2667 MHz DDR4

Updated to Big Sur the other day - computer is borderline unusable now. Delays are everywhere - typing, moving windows, opening programs. GIMP-2.10 became practically unusable, with insane delays for even most basic actions (not that I really care much about GIMP, but it used to work just fine, and now it doesn't, and delays are most obvious in that program). I regret updating so much.
iMac (Retina 4K, 21.5-inch, 2019)
3,2GHz 6-Core i7
32GB DDR4

My iMac worked fine after the first reboot, except that I could not watch anything on Netflix or on any other streaming service anymore (the screen just went blank after a few seconds, but the sound was still working), but it works with Chrome.
And after today's boot it's SO damn slow! It took several minutes until I could open any apps and Safari crashed multiple times.
Fix this, Apple!!
27” IMAC 2017 is having same problem after installing Big Sur OS. Very slow operating and high level of frustration in waiting for the computer to respond. Spent 2 days on the phone with Apple Support without resolution. Last thing done was to reinstall Big Sur OS. This was done twice and did not resolve problem. Now Apple Support is recommending to back-up drive so it can be wiped clean and start over. Big lesson learned, I did not backup computer before the first download of Big Sur OS. Now they say there is no going back.
Same here - my iMac – 2019 / 3,8 Ghz / 16 GB Ram – is practically unusable.
Same with my MacBook Pro 2019 Retina. Catalina was perfectly fine but Big Sur has ruined the experience. Pretty much every aspects feels slow and janky, and I'm unsure about the mobile-device feel of Big Sur - would revert to Catalina if it was quicker and easier to do so.
Same here with my Macbook Pro – 2018 / i7 2,9 Ghz / 16 Go Ram / SSD 500Gb...
Bottom Line: Big Sur is a Disaster! Like many people, if this isn't fixed fast, my Mac days are over!
Upgrading to Big Sur has been a disaster - as others have noted my MacBook has become a jittery, slow response frustrating experience. Apple - you guys better get this figured out quick ! Its ridiculous.
MacBook Pro (15-inch, 2017) 16GB RAM with 2,9 GHz Quad-Core Intel Core i7
The window animation is terrible (when opening preview of images/videos/etc), minimizing, maximizing, even when scrolling pages in Chrome, but in Safari is fine. All my apps are up to date.
It's like is running with 5fps!
Hello, I'm having the same issue with my notes and reminders app lagging with the new Big Sur update on my 2017 MacBook Pro. It's extremely frustrating and make the apps unusable. It's also worth mentioning that the notes and reminders apps also lag on my new 2020 iPad Pro. This is an urgent and important issue that the development team needs to prioritize.
Dear Apple developers,
after downloading Big Sur to my iMac (Retina 5k, 2017, 4,2 ghz quad_core, intel I7) the performance became terribly slow. I am working as professional photographer and photo editor and this upgrade is a disaster in regard to the speed of starting up and performance in general. Under Catalina my processing workflow was fully satisfying, in speed and switching between the several software packages which I am simultaneously running (Adobe Photoshop, Lightroom, ON1, NIK, etc).
Please fix it!

iMac slows down after Big Sur installing
 
 
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