Slow Wifi on my 2021 MacBook Pro M1 Pro 14in

ACuculich Said:

"Slow Wifi on my 2021 MacBook Pro M1 Pro 14in: I cannot for the life of me figure out why my 2021 MacBook Pro M1 Pro 14in is the ONLY device in my house getting significantly slower wifi speeds than the rest of my house.[...]"

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Troubleshooting Lagging Mac WiFi:

Some Things you Can Try:

A. Single Out this User:

See what happens when you create a new Administrator user. Log in to it, seeing if anything is different. If it works, then it is something misconfigured in this current user.

B. Remove Login Items:

Go To: System Preferences > Users & Groups > Click your Username > Login Items > Rid of Terminal, and remove any unnecessary items.

C. Reset the SMC and your NVRAM:

Sometimes when changes are made to the system(i.e. updates), system configurations (i.e. for the keyboard) become manipulated, technically. So, reset the SMC and NVRAM.

D. Try Safe Mode:

[Hold Down shift key] upon boot. In Safe Mode, corrupted system setting files (caches), are intentionally fixed.

1. Boot: in Safe Mode
2. Log In: as Same User
3. Wait: 30 seconds 
4. Shut Down: the Mac
5. Wait: 30 seconds 
6. Boot: the Mac normally
7. Log In: as Same User
8. See if can get this to work

Hold down the Option key while you click on the Wi-Fi icon on the menubar. screenshot or transcribe the snapshot of operating parameters that show up. looks like this older version:

also, how many Networks do you see?

<< I live in a larger apartment building, there are a few dozen other networks that show up "Other Networks", but I have never connected to any of them. >>

The number of other networks in your 'Network Neighborhood' AND the 80 MHz width of the channel you are attempting to use on Wi-Fi-6 may be a deadly combination. Each other Router whose name you can see is using up Spectrum, and crowding your data, threatening to clobber it frequently. Wi-Fi-6 is great for you when there is no competition, but is prone to getting clobbered in apartment building setups, especially at wider channel widths like 80 MHz.

Here is an example of Crowded spectrum:

anything transmitted in the same part of the spectrum at the same time clobbers the others nearby, not just on the same nominal channel.

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After thinking about this for a while, I have no explanation.

That generally means there is more to the story that is not yet understood. When that happens, I try to go back to see if anything unusual was happening, to see if that might provide a clue.

Your Option-Wi-Fi snapshot reported certain numbers (RSSI, MCS index) that seemed excellent, along with others that were inconsistent and simply did not fit (Transmit rate, NSS).

It is possible you have a hardware issue, or something really wonky in your 'network neighborhood'. If you go to the Genius Bar, that takes you to completely different 'network neighborhood' where everything around you has been programmed and debugged to provide great coverage. They will likely tell you "No Fault Found". [different from "all is well" but no more helpful].

I recommend you start again at the Option-Wi-Fi menu, and choose Network diagnostics and wait a moment while it draws its menus. There are several appropriate tools there, and one that is a waste of time UNLESS working with an Apple Network Engineer.

General Recommendations can helpful.

on the Window menu, SCAN (Option-Command-4) gives you a chart of all the network visible, and what channel they are using, like this older one:

I live 'in the woods', so my chart is very different from what you will get.

NOT HELPFUL: 'Diagnostic report' saves every setting that could possibly influence your network in a file that grows so large, it has to be compressed. No user-readable information is provided.

Your next step may be to contact Apple support, work with the first responder through the obvious possibilities, then ask for a Wi-Fi specialist:

Official Apple Support

N.B> do not let them tell you its is fine (unless it actually IS fine), or they are helpless to provide further assistance.

You have excellent raw signal (RSSI) signal. We expect to see numbers closer to zero than -50 when you are right nearby, and as signals fall off, they approach -65, where your Mac will attempt to make any better connection it can. you must be right next to a Router.

noise is acceptably quite low. You have connected on the more noise-immune 5GHz band, using channel 48, but that 80 MHz width may be problematic in crowded environments, because Wi-Fi 6 symbols are longer duration and get clobbered by neighboring traffic.

MCS index 11 says you are using the maximum number of patterns per signaling interval, 1024. That should yield a data rate of 567 per antenna, and NSS=2 says you are using two antennas. But you should therefore be getting four times that data rate. This is a puzzle to me.

Those numbers in isolation should allow you to achieve close to the advertised Internet data rates. if you are not seeing that throughput, it could be because of background sync-ing software such as OneDrive, Dropbox, BackBlaze, or similar software that is hogging bandwidth, rarely due to sync-ing photos to iCloud. Or possibly due to Virus scanners or similar junk-ware, or possibly use of a VPN you installed yourself (not an Institutional VPN).

EDIT: adjusted using corrected numbers, and this is even more puzzling, unless the parameters were changing as the report was created.

I am not sure if you are still working on this, but I have two recommendations.

First is to set your Router (and Mesh Access points) back to from 80 to 40 MHz channel-width. That still leaves you up to 286 M bits/sec on each of two antennas. The reason for doing this in crowded apartment buildings is that when you are using less spectrum, your data symbols will get clobbered less often. (reduces interference from others)

The second recommendation is to set channel selection to 'Automatic' if not already set that way. When each access point wakes up, it sniffs the airwaves for competing traffic, and uses a less-busy channel for your data. This also reduces competition. It is not an accident that every Wi-Fi debugging procedure starts with "cycle the power to your Router".

<< So, if the spectrum in my neighborhood is only causing an issue on my MacBook Pro, what is so special about the new M1 Pro MacBook Pro 14" that means it's so sensitive to the networks in the vicinity, ... >>

A: Exactly Wi-Fi-6 (802.11ax). Your older devices fall back to Wi-Fi-5 (802.11ac), and have far less issues in a crowded environment.

Wi-Fi-6 has many new features, most of which are beside the point unless you are providing coverage over a building-wide area. But one sticks out. OFDM means that Wi-Fi-6 symbols persist longer, and are therefore easier for other Routers using nearby spectrum to clobber.

This introduces OFDM symbols that are four times longer: in 802.11ac, an OFDM symbol takes 3.2 microseconds to transmit. In 802.11ax, it takes 12.8 microseconds (both without guard intervals).

from Wikipedia article on Wi-Fi-6

That is why's some users have seen better throughput when dropping back to 40 MHz wide channel (in crowded 'network neighborhoods'.

as I posted above:

Your next step may be to contact Apple support, work with the first responder through the obvious possibilities, then ask for a Wi-Fi specialist:

Official Apple Support

N.B> do not let them tell you its is fine (unless it actually IS fine), or they are helpless to provide further assistance.

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They have a team of Network specialists. You have to do your 'due diligence' with the first responder, and once you have exhausted their ability to help, press them to send you to a specialist. (That specialist is not likely to be in the same office, so it may be a call-back).

They can easily look at this discussion for supporting information (e.g., screenshots). But they always want to discover any conclusions for themselves.

¿Do the numbers in your snapshot stay stable? was the one you posted the one you always get?