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iMac randomly slow internet until reboot

I have the newest 2020 iMac (latest Big Sur OS), connected via wifi to my google wifi router. Speeds at the router and on other devices are usually about 400mb/sec. On my iMac, after a "random" while of usage, it will drop to about 100mb/sec or less and stay that way until I reboot. (Zoom will tell me I have a bad connection, etc.) Even turning off/on my wifi doesn't help. Any suggestions? I cannot find the cause. So annoying!

iMac 27″, macOS 10.15

Posted on Feb 11, 2021 7:35 AM

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Question marked as Top-ranking reply

Posted on Feb 11, 2021 7:52 AM

Please navigate to the Mac App Store or navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.


When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 


For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211


9 replies
Question marked as Top-ranking reply

Feb 11, 2021 7:52 AM in response to WebDevGuy

Please navigate to the Mac App Store or navigate to www.Etrecheck.com and download the free version of EtreCheck. Once you have you downloaded the app and installed it, please run the report and save it. This report will help us get a good idea what has been installed on your system and help us be able to diagnose what may be wrong.


When you have your report, you can attach it when you reply to this message and we can then review it and help you determine what is needed to get your system running well again. 


For instructions on how to download your EtreCheck report and attach it to your reply to this message please click https://discussions.apple.com/docs/DOC-250000211


Feb 11, 2021 9:25 AM in response to WebDevGuy

The issue could be the DNS settings you use. If you have never changed them from the default your ISP provides that is a frequent cause. Here is an article that provides some insight and how to change them to something more stable than the ones your ISP uses.


https://support.apple.com/en-gb/guide/mac-help/mh14127/mac

https://www.cnet.com/how-to/how-to-change-dns-windows-mac-osx/

Feb 11, 2021 10:22 AM in response to WebDevGuy

  • Try restarting in Safe Mode and then restarting normally and then re-test.
  • Other than that I'd suggest you read the following article (OSDaily is an excellent resource). https://osxdaily.com/2020/11/23/how-fix-macos-big-sur-wifi-issues/
  • Ensure you have updated Big Sur to 11.2.1, this release came out earlier this week.
  • If you continue to have problems, then your next stop would be to contact AppleCare for support directly from Apple.

iMac randomly slow internet until reboot

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