Slow Wi-Fi on MacBook Pro 14" when Bluetooth is on

[YourDamnCroissants]

I just received my 14" M1 Pro and I'm having an issue with Wi-Fi speeds when Bluetooth is on. With Bluetooth on, the new MacBook tops out around 40mbps sustained download speeds, while the Intel machine it's replacing and an iPhone 13 Pro easily reach above 300mbps (all on the same VHT80 5GHz network). Signal strength and SNR in the room I'm in is good (see screenshot) and has not changed recently.

When I turn Bluetooth off, either by entering Recovery mode or turning it off via System Preferences (not Control Center, I wonder if it's doing that "disable new connections but keep the chip on" thing iOS does), speed tests show 550mbps+ download speeds. Once Bluetooth is turned back on, that crashes back down to 40mbps. Ethernet runs at full speed regardless (>1gbps on my Xfinity Gig plan).

Anyone have a similar issue or a solution to it?

 

[arw]

In case you missed it, your BSSID is only redacted in the post itself, not the attachment.

- Have you tried reseting the Bluetooth module:
https://www.macrumors.com/how-to/reset-mac-bluetooth-module/
- To disable Bluetooth (not disconnect, as you already suspected) via Control Center, you can click the extend symbol “>“ besides the Bluetooth icon, then you should see a real toggle switch.

On a sidenote:
I have a similar issue, although it‘s in a 2,4 GHz WiFi environment.
I have a ticket open at Apple with the most recent session, testing and logging on Monterey 12.1.
They are definitely looking into the issue and planing on fixing it (Bluetooth interfering heavily with integrated WiFi).
That being said, Bluetooth and 2,4 GHz WiFi (as well as USB 3.0) are expected to interfere with each other with an accepted drop in throughput of 10-20% - I‘m seeing up to 100%.
Your 5 GHz on the other hand shouldn‘t be affected.

 

[YourDamnCroissants]

In case you missed it, your BSSID is only redacted in the post itself, not the attachment.

- Have you tried reseting the Bluetooth module:
https://www.macrumors.com/how-to/reset-mac-bluetooth-module/
- To disable Bluetooth (not disconnect, as you already suspected) via Control Center, you can click the extend symbol “>“ besides the Bluetooth icon, then you should see a real toggle switch.

On a sidenote:
I have a similar issue, although it‘s in a 2,4 GHz WiFi environment.
I have a ticket open at Apple with the most recent session, testing and logging on Monterey 12.1.
They are definitely looking into the issue and planing on fixing it (Bluetooth interfering heavily with integrated WiFi).
That being said, Bluetooth and 2,4 GHz WiFi (as well as USB 3.0) are expected to interfere with each other with an accepted drop in throughput of 10-20% - I‘m seeing up to 100%.
Your 5 GHz on the other hand shouldn‘t be affected.

Good catch on the attachment.

Monterey removed that debug option in the Bluetooth menu. I tried killing bluetoothd but that had no effect, unsurprisingly. And there's no Bluetooth plist in /Library/Preferences to delete.

I'm seeing a few posts about the issue on Reddit, with one suggesting it started with macOS 12.1. I'm hoping the bugfixes in 12.2 resolve it, might try installing the public beta of the RC this weekend to test it out. I submitted the issue through Feedback Assistant and will reach out to support over the weekend as well.

 

[YourDamnCroissants]

I've found the following Reddit threads that appear to be discussing the same issue:

1. https://www.reddit.com/r/apple/comments/rhj7sr
2. https://www.reddit.com/r/macbookpro/comments/qgi4iw

 

[arw]

Monterey removed that debug option in the Bluetooth menu. I tried killing bluetoothd but that had no effect, unsurprisingly. And there's no Bluetooth plist in /Library/Preferences to delete.

Previous connected devices should be stored here

/Library/Bluetooth/

But as you are not the only one, chances are good it gets fixed soon.

 

[YourDamnCroissants]

Problem persists on macOS 12.2 GA

 

[l3n0x]

Interesting, I also have a 14" MBP and it doesn't have this issue. Right now I'm connected with a Bluetooth mouse and running speedtest gives me 250mbits.
My access point is wifi5, if that matters (so AC 5GHz and channel 44)

 

[jezbd1997]

No issues here.. 14" Pro and have used the machine with Bluetooth on the entire time i've owned it

 

[thomasparra]

I have this issue on my MBP 2019 over 5GHZ wifi. I have investigated on my own since the issue appeared about 1-2 months ago (I am not sure if it was before or after the update from Big Sur to Monterrey)

After various tests, I can confirm it is very likely a software issue within Mac OS

When Bluetooth is on, the bandwidth is affected as it varies a lot from 60 to 230 Mbps over a 15 sec speediest. I also encounter jitter, and packet losses. Also, when testing the local network with ping 192.168.1.1, I have huge spikes in latency (from 5ms to 200 ms...).

When Bluetooth is off, I run at 350-400 Mbps constantly and no more latency issues (from 3 to 11 ms over 192.168.1.1).

I hope they fix it soon. Not sure if resetting the bluetooth module would help. Please note that the MacBook Air M1 2020 seems to handle this a bit better. I still see some spikes in latency when bluetooth is on; but it seems more minor in terms of frequency and time.

 

[Sanpete]

I have this issue on my MBP 2019 over 5GHZ wifi. I have investigated on my own since the issue appeared about 1-2 months ago (I am not sure if it was before or after the update from Big Sur to Monterrey)

After various tests, I can confirm it is very likely a software issue within Mac OS

When Bluetooth is on, the bandwidth is affected as it varies a lot from 60 to 230 Mbps over a 15 sec speediest. I also encounter jitter, and packet losses. Also, when testing the local network with ping 192.168.1.1, I have huge spikes in latency (from 5ms to 200 ms...).

When Bluetooth is off, I run at 350-400 Mbps constantly and no more latency issues (from 3 to 11 ms over 192.168.1.1).

I hope they fix it soon. Not sure if resetting the bluetooth module would help. Please note that the MacBook Air M1 2020 seems to handle this a bit better. I still see some spikes in latency when bluetooth is on; but it seems more minor in terms of frequency and time.

What about your results makes you think it's software?

 

[thomasparra]

What about your results makes you think it's software?

Having ran the scenarios through two different Macs and finding repeating consistent instances of connectivity issues, how could this not be software?

 

[Sanpete]

Having ran the scenarios through two different Macs and finding repeating consistent instances of connectivity issues, how could this not be software?

Well, it could be hardware issues on both machines. But if it's associated with software updates, that would be a strong clue.

 

[throAU]

Bluetooth and Wifi 2.4ghz use the same band, and thus bluetooth will be consuming some of the WIFI spectrum.

If you don’t have a 5.8Ghz wifi access point, its probably time to upgrade.


edit:
sounds like the above is not your issue in particular, but it is AN issue…

 

[YourDamnCroissants]

I've narrowed down this issue to the awdl0 virtual network interface, which is how macOS represents the ad-hoc WiFi connections it establishes for Continuity features like AirDrop. I believe this stops functioning when Bluetooth is turned off, because the features use both WiFi and Bluetooth in tandem. Similar to what happens when the OS scans for WiFi networks, when this interface is used for AWDL, it has to "steal" the WiFi antenna briefly. Not enough to disrupt the connection, but enough for us to notice the ping spikes and varying limits on bandwidth it causes.

On the systems I've tested, disabling the awdl0 interface stops the OS from carrying out AWDL-related tasks, leaving the WiFi chip undisturbed. You can test this yourself by running "sudo ifconfig awdl0 down". The ping and WiFi throughput should stabilize.

There's lots of documentation of folks running into this since Yosemite: https://medium.com/@mariociabarra/w...t-yosemite-wifi-and-awdl-airdrop-41a93eb22e48

You'll find most of the reports on subreddits and forums for real-time applications, where users would be most likely to notice the kinds of subtle issues that this issue causes. Google Stadia actually recommends disabling the awdl0 interface to resolve connectivity issues on macOS: https://support.google.com/stadia/answer/9595943?hl=en#zippy=,mac-and-ios-troubleshooting

I documented this in a bit more detail in a Reddit thread, including system logs showing the AWDL activity correlated with the ping spikes: https://www.reddit.com/r/macbookpro/comments/qgi4iw/_/hw37uh8

 

[weltraum]

I have the exact same issue. When I graph the ping to my router with `gping` the results are all over the place as soon as I’m turning on my iPhone. WiFi throughput goes down from 400mbps to about 20-40mbps. Taking down the `awdl0` network interface fixes it, but this cannot be a permanent solution. Now that I know what’s causing it, I can even reproduce it on my iPhone and iPad. I never cared about the fastest WiFi connection with these devices, but turning off Bluetooth increases the throughput a lot. Do you by any chance use a Ubiquiti access point? I have tried 3 APs now and the problem is by far the worst with my UAP FlexHD.

 

[weltraum]

I used Wireshark to listen on the `awdl0` network interface and I saw that my iPhone was non-stop sending out a large number of messages to my MacBook (and presumably other nearby Apple devices). No other device was doing this. I rebooted the phone and the problem is completely gone. WiFi throughput still drops for a few seconds when sending messages via awdl, for example when opening the airdrop sharesheet, but this is acceptable.

 

[newmacsnail]

I recently picked up a MBP 16'' Max (10/32 cores, 64GB of RAM) and I'm also having the same WiFi issues.
At first I noticed that I was not getting the same speed as my iPhone on WiFi 6. The MBP topped up at 300Mbps, while the iPhone easily reached 700 to 750Mbps.
After some research I noticed that disabling Bluetooth fixed the issue and after more research I found this thread and read about the awdl0 interface. And in fact, the moment I issue the command sudo ifconfig awdl0 down fast.com reports a very stable download and upload speed of around 750Mbps. This all while keeping BT on.
Wireshark did not show a lot of packages on the interface, so I have no idea what the problem may be.
The AP I'm using is a UniFi U6 Pro. Curious if this happens on other AP's too.

I also noticed that there is a lot of packet loss on WiFi when using certain applications that require lots of bandwidth and low latency like NVIDIA GeForce NOW when the awdl0 interface is up. Disabling the interface will fix the packet loss right away and make the GeForce NOW service usable again.

Now, this makes me a little upset as this is not really "Pro" performance. What makes me even more upset is that this is a well known problem, already present years ago on Yosemite as @YourDamnCroissants found out.

I already sent Apple feedback about this, but I have little hope of this getting fixed. Anything else we can do?

 

[fromgophonetoiphone]

Hmm. This seems to be the most technical explanation so far. Most other threads have too much noise because WiFi performance for average users can vary so much (slow network setups, poor reception, range, etc.), and when asked to wire up, this will never be an issue.

Quite annoyed for instance the 12.4 update downloaded for me at 2-3 MB/sec and took forever. When I did the 12.3.1 update, I remember my MBP chugged along at 2-3 MB/sec for a good few minutes and then I saw it open up to 30-40 MB/sec (generally what WiFi maxes out at for me). It seems very unpredictable when it wants to speed up versus stay slow.

 

[emilkeriksen]

I've narrowed down this issue to the awdl0 virtual network interface, which is how macOS represents the ad-hoc WiFi connections it establishes for Continuity features like AirDrop. I believe this stops functioning when Bluetooth is turned off, because the features use both WiFi and Bluetooth in tandem. Similar to what happens when the OS scans for WiFi networks, when this interface is used for AWDL, it has to "steal" the WiFi antenna briefly. Not enough to disrupt the connection, but enough for us to notice the ping spikes and varying limits on bandwidth it causes.

On the systems I've tested, disabling the awdl0 interface stops the OS from carrying out AWDL-related tasks, leaving the WiFi chip undisturbed. You can test this yourself by running "sudo ifconfig awdl0 down". The ping and WiFi throughput should stabilize.

There's lots of documentation of folks running into this since Yosemite: https://medium.com/@mariociabarra/w...t-yosemite-wifi-and-awdl-airdrop-41a93eb22e48

You'll find most of the reports on subreddits and forums for real-time applications, where users would be most likely to notice the kinds of subtle issues that this issue causes. Google Stadia actually recommends disabling the awdl0 interface to resolve connectivity issues on macOS: https://support.google.com/stadia/answer/9595943?hl=en#zippy=,mac-and-ios-troubleshooting

I documented this in a bit more detail in a Reddit thread, including system logs showing the AWDL activity correlated with the ping spikes: https://www.reddit.com/r/macbookpro/comments/qgi4iw/_/hw37uh8

I registered just to say thank you. I work for a small business and we've been having WiFi issues for a long time. I put it down to our equipment but after spending all day with a few Macs on macOS 12.4 that had especially bad network issues I came across your fix. It completely solved the issue on those computers and it greatly boosts speeds on our other Macs. I think you just saved us several thousand $.

 

[tuxkilla]

In an era where the internet has so much misinformation, this thread FINALLY gave me some insight as to what is happening with my UniFi FlexHD routers and my M1 MacBook Air. I tried probably 10 different firmware versions from 4.x to the latest 6.2.30, and have been running into abysmal performance on both the 5g and 2.4g network. I have been seeing only ~10 Mpbs down, only to have a super random spike to ~500 Mpbs down. If I switched back to my ancient Archer C7 router on a test 5g network, the problems would somewhat go away, but I could not get full WiFi throughput, even sitting right next to the wireless base stations. As soon as I ran 'sudo ifconfig awdl0 down', my speed tests went back to ~500 Mpbs consistently, and I can FINALLY watch HD movies while using my bluetooth headsets. I see countless posts on ubiquiti's forum about mac issues, I wonder if this will fix what they have been seeing for years. Looks like this popped up in an older MacOS release? Thanks again for the help everyone.