Slow wifi after Big sur update
After updating to Big sur my wi-fi speeds are at about a third of what i’m used to. Right now i get something like 50-100mbit/s both ways on my macbook and 350-400mbit/s on my iphone that is right beside the computer. I’m on a 500mbit connection and I use the same 5ghz network on both devices. Before updating I got the same speeds on both devices.
Posted on Dec 21, 2020 1:02 PM
Guys I think I may have found a solution for this problem.
- Turn off bluetooth.
- Disconnect all peripherals from your computer.
- Open System Preferences. In the «Energy Saver» preference, de-select «Wake for network access» (no check, and leave it that way).
- Open the finder. Select the «Go» menu. Select «computer.» Select «Macintosh HD.» Go the the «Library» folder. Go to the «Preferences» folder. Find the preference file «com.apple.bluetooth.plist.»
- Rename «com.apple.bluetooth.plist» as «com.apple.bluetooth.plist.old» (i.e. add «.old»). Eventually, if this solution works for you, you can delete this «old» preference file.
- Restart your computer (this will create a new «com.apple.bluetooth.plist» preference file).
- Turn bluetooth back on.
Apparently, the problem is a bug caused by a bad interaction between the bluetooth preference file and wifi.
User level: Community Specialist
We’re glad you thought to ask Apple Support Communities about the slow network speeds you’re experiencing after installing macOS Big Sur. We want to help! You’ve completed some great steps so far, so let’s see if we can narrow it down further. If you haven’t already, use Wireless Diagnostics to see if it reports: Use Wireless Diagnostics on your Mac
To help isolate and narrow our focus we’ll also want to test this while using safe mode, a new user account, and macOS Recovery. Safe mode will tell us if a third-party app is possibly causing this to happen. Here’s more information on safe mode and how to start there: How to use safe mode on your Mac
After noting the results of safe mode, restart your Mac normally to exit, and we’ll then create a new user account to test. Please do not use the Guest account. This will let us know if the issue is with your account only, or system-wide: Set up users, guests, and groups on Mac
After noting those results, we’ll start to macOS Recovery and use the option to Get Help Online. This takes macOS completely out of the equation: About macOS Recovery on Intel-based Mac computers
Keep us posted on the results.
I have the same issue. In my case, I bought the M1 (upgraded from MacBook Air 2013 running on High Sierra). The file transfer speeds over the network have drastically reduced when on WiFi. The same issue doesn’t happen with ethernet. Tried all the possible tweaks adjusting the Wifi 5Ghz channels and width on the router but no change in the file transfer speeds at all.
Hi! I’m glad I found this thread. I’m having exactly the same issue. Running macOS 11.1 (20C69) Wifi speeds are much slower (only one third or one half of the speed on all my other devices). But the strange thing is: It happens only after some time. Directly after reboot I get full speed of 500-600mbps. But then after 5 to 10 minutes I’m only getting about 150-250mbps. Then nothing can bring back the faster speeds.
- resetting PRAM/SMC
- completely removed wifi adapter under network settings and added new one
- removed wifi preferences
- I’m not using any firewall/antivirus-software
- changed wifi 5ghz channels, MTU size, CTR threshold
- optimized all settings on my router
- killed all background processes and unnecessarily running apps
- disabled timemachine backup
Nothing is working. But all other apple devices in this house (two iPhone 11 Pro, iPad Pro and so on) get 500-600mbps very single speedtest. Just my mac doesn’t get the full speed. And honestly this was by far the most expensive Apple product I’ve ever bought (2849€). So that’s driving me crazy.
We need a fix for this problem!
Big thanks for your reply!
I have narrowed it down to bad speeds in regular mode and my regular good speeds when i’m in safe mode. I did also do the same tests on my partners macbook pro (same model, a bit newer) that is still on Mojave (10.14.6) and get the almost the same results (bad speeds in regular mode, but not as bad as on mine, good speeds in safe mode). The problems on my macbook did not occur until i updated to Big sur though..
What might be the next step?
User level: Community Specialist
That’s good to know. What happened in the test user account, and did Wireless Diagnostics report any issues? You may consider creating a new network location to see if settings there are causing this: How to use network locations on your Mac
Also, since the speeds pick up in safe mode, check the steps under «If the issue doesn’t continue in safe mode» here: How to use safe mode on your Mac
When using the test user account i got bad download speeds and great upload speeds for a couple of tries. After that i got the same results as with my regular account.
The Wireless diagnostics got the following results:
Fundamental connection error
All of the above errors are still there after rebooting the router. I have a total of 4 units connected to my wifi (iPhone, MacBook and two Sonos speakers) and 2 units connect by ethernet cable (NAS and tv). None of the other units is that active (NAS mostly 1-2 kb/s up/down).
I’ve also made sure that the routers wireless channel mode is set to auto
I did not have any Start up objects to remove
I added a new network location and did a wireless diagnostics which got me the fundamental connection error but no channel overload
User level: Community Specialist
Great information! With the alerts you’re seeing in Wireless Diagnostics, use the following resource to help with the settings for your wireless router. You may also need to work with your internet service provider for help with the settings: Recommended settings for Wi-Fi routers and access points
I tried everything above with Apple tech, with no resolution of my problem. I’m getting ~8-10 Mbps download speeds on my MacBook w/Big Sur and ~100Mbps on my other macs running Catalina. This is a glitch that has occurred after updating from 11.01 to 11.1.
Yes! Thanks for confirming. That’s driving me crazy. The device that was the most expensive by far only has one third of the download speed of all my other devices. very very disappointing. Hoping for Big Sur 11.2
So i updated to Big Sur 11.2 and my speeds got a bit better but still not ok. Something like 100-150mbit/s down and 50-60mbit/s up on my macbook while getting 350-500mbit/s both ways on my iphone.
Did the wireless diagnostics again and don’t get any errors at all.
Any ideas what i could try?
Oh i tried uploading some files to my NAS as well. The NAS is connected to my router by cable and i used the wi-fi for my computer.
It did 10gb in 5 minutes which would be something like 260mbit/s if i’m not misstaken?
Could it be that my problem only occurs with external traffic?
User level: Community Specialist
That’s great to know! Since the issue happens with uploading to your NAS too, we recommend reaching out to your internet service provider to have them look into things on their side. If they don’t find any issues, reach Apple Support to look into this more. They can be reached here: Get Support
Thanks again, and have a wonderful day.
I can confirm that the issue is still there with Big Sur 11.2. And I am 100% sure that the issue only happens in Big Sur.
I did a lot of testing, changed the Channel of 5GHz Wifi, optimized all settings, wrote with netgear support and double-checked everything. None of my other devices is having issues. So I decided to test if it’s an hardware-related or software-related problem.
So I just installed macOS Catalina to an external USB drive and started testing.
Here are the results (I did two days of testing):
In Catalina I constantly get 450-600Mbit/s of download speed:
And on Big Sur I get 600 Mbit/s as well, for the first minutes after rebooting. But then — say after 15-20 Minutes, or after waking up from standby — I only constantly get half of the download speed, only 250-300 Mbit/s:
This is so mysterious. I repeated the speedtest many many times and the MacBook Pro from 2018 was on the exact same position on my desk, right next to the Orbi RBS50 Satellite and connected with 5Ghz to the same BSSID. The T/x rate is at 866Mbit/s, even when getting the «low» download speeds.
This absolutely is an evidence for me that the problem is either correlated to Big Sur or any other Software issue. But as I said, I tried everything (new user account, removing Wifi .plist and bluetooth .plist files, creating new network location, removed SCM/PRAM, I don’t have any antivirus or firewall installed, Wireless diagnostics didn’t found anything, and so on and so on. ).
Also the problem only exists on Wifi, I get full speed over ethernet. Also when pinging for example google.com on wifi, I get a spike or some drop-outs, so the wifi connection isn’t stable.
I am happy for any help or feedback!
Что делать, если на Mac плохо работает Wi-Fi
На протяжении многих лет пользователи Mac сталкиваются со сбоями в работе Wi-Fi. Разрывы соединения, отсутствие доступа к сети, низкая скорость передачи данных — если вам всё это знакомо, не спешите винить своего провайдера. Вполне возможно, что источник проблемы находится прямо перед вами. В этой статье мы рассмотрим наиболее эффективные варианты решения проблем с Wi-Fi в macOS.
Способ первый — полный сброс настроек
Самый простой и в то же время самый результативный метод. В большинстве случаев помогает раз и навсегда решить проблемы с беспроводным подключением. Ну, или до тех пор, пока вы не поставите очередное обновление macOS 🙂
- Открываем Finder и переходим по следующему адресу: /Library/Preferences/SystemConfiguration/
- В открывшемся окне находим и удаляем следующие файлы:
com.apple.airport.preferences.plist
com.apple.network.eapolclient.configuration.plist
com.apple.wifi.message-tracer.plist
NetworkInterfaces.plist
preferences.plist
- После удаления сетевые настройки Mac будут сброшены по умолчанию. Перезагружаем наш компьютер.
- Всё, что осталось — это заново настроить подключение по Wi-Fi.
Способ второй — создание сети Wi-Fi с кастомным DNS
Этот вариант для тех, кто столкнулся с низкой скоростью при использовании беспроводного соединения. Создав сеть с собственными DNS-серверами, мы сможем уменьшить сетевые задержки и пинг, а также увеличить скорость загрузки сайтов. Для этих целей мы будем использовать сервис от Cloudflare.
- В открывшемся окне нужно будет создать новую сеть. Для этого жмём на значок «плюс».
- Подключаемся к созданной беспроводной сети.
- В настройках сети жмём на кнопку «Дополнительно» и переходим во вкладку «TCP/IP». Слева находим пункт «Запросить адрес DHCP».
- Переходим в раздел «DNS». В левой части программы добавляем новый сервер. Указываем следующие адреса: 1.1.1.1 или 1.0.0.1.
- В разделе «Аппаратура» настраиваем пункт «Конфигурация» выбрав «Вручную».
- Изменяем параметр «Макс. размер пакета (MTU)» на «Пользовательский». Чуть ниже вводим значение 1453.
- Всё готово — чтобы настройки вступили в силу, нажимаем «Применить».
Способ третий — сброс кэша DNS
В том случае, если веб-страницы отображаются неправильно, а скорость загрузки сайтов оставляет желать лучшего — необходимо выполнить процедуру сброса кэша DNS.
- Открываем приложение «Терминал». Это можно сделать через Spotlight либо другим удобным способом.
В появившемся окне вводим следующую команду, в зависимости от текущей операционной системы:
Catalina: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
Mojave: sudo killall -HUP mDNSResponder; sleep 2; echo macOS DNS Cache Reset;
High Sierra: sudo killall -HUP mDNSResponder; sleep 2; echo macOS DNS Cache Reset;
El Capitan: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder;
Yosemite: sudo dscacheutil -flushcache;sudo killall -HUP mDNSResponder;
Mavericks: dscacheutil -flushcache;sudo killall -HUP mDNSResponder;
Lion & Mountain Lion: sudo killall -HUP mDNSResponder;
- Вводим пароль администратора. Если всё прошло успешно, на экран будет выведена надпись macOS DNS Cache Reset.
- Перезагружаем наш Mac. Всё готово!
Теги: Инструкции для Mac macOS Catalina Инструкции для Mac проблемы сеть