Teams client kills network performance

Copper Contributor

Hello.  I have two Microsoft Surface devices, one SB2 and one Surface Laptop 2, both on Windows 10.  Both of them, over the last few months, have experienced significant wifi and wired network slowdown.  I have 1.2Gb Xfinity service and I was lucky to get 100Mbps speeds on Ookla and Xfinity speed test sites.  I've spent time with Comcast people analyzing my Gateway, testing my connected devices, etc. to no avail.  To them, everything was provisioned and functioning correctly. 


They suggested that maybe it was an app running on my laptops, or perhaps a windows config setting.  Since I run the Teams client on both devices, on a whim, I signed off and killed the Teams client, and magically, my network speed came back to where it should be.  I repeated the speed tests over 10 minutes or so just to make sure it wasn't a fluke, but it remained fast.  So I restarted the Teams client, and I was right back where I started, at 60-90Mbps, and rarely above.  I repeated stopping and starting Teams on both laptops and checking speed multiple times and sure enough, Teams was the culprit.  So for the time being, I'm using Teams from the browser which doesn't seem to have this problem, but would love to know why this is happening.  BTW, this happens when Teams is idle, so it's not just when there are active meetings.


I saw another post on a MS forum about soemthing similar, but there wasn't really any resolution.  Coincidentally, this person also was using a Surface device.  



16 Replies

@StaceeFrane, please note that the reason I posted this reply, referencing this additional post, is that it is an example of another person having the same problems that I have seen. However, there are no useful answers in that post and this problem still remains. Clearing the cache is only a temporary fix, and it doesn't take long for the problem to return. Also note that after continued use of the Teams Web client over the past 2.5 weeks (I have abandoned the Windows client), performance degrades as well. As suggested by the OP in the other thread, perhaps this is a problem with Windows since other video conferencing platforms seem to have similar issues ,but since Windows and Teams are both MS products, it would be great to get this fixed.

I will hand this off to an engineer on performance and ask them to follow up. Thank you.

@garygraeff Sorry to hear you're having this problem. Let's dig into this a bit further.. I read the previous post as well and it looks like this seems to be happening after the initial login process.. Can you provide detailed steps that you can help pinpoint about the specific timeframe for when you see this? An example would look like;
- At 4:42:00, I launched SpeedTest, showing X upload/download speeds, then launched Teams.

- At 4:42:10, Teams fully launched, still showing X upload/download speeds.

- At 4:43:05, SpeedTest is now showing Y upload/download speeds.

- At 4:45:06, SpeedTest is still showing Y upload/download speeds.

- At 4:45:00, I killed the Teams.exe Process, and SpeedTest went back to showing X upload/download speeds.


When clearing cache (Sign-out also clears cache), there's a rebuilding process that takes place for the app to try and rebuild that cache so you have a better experience when in the app. That's expected to take some network speeds with it as it's downloading history/etc. Even when the app is idle, we're still making continuous calls to the service to ensure you're continuing to have things up-to-date (presence, chat feeds, notifications, etc), that can also continue to require bw speeds. But in your case, looking to understand the specific repro steps that cause this in your case to see if there's indeed a real problem here from the Teams side, or if there's a network processing issue locally via the OS.



Sam Cosby, Teams Engineering PM

Thanks for your help on this. Here's the first pass of my testing this morning:

Rebooted laptop and restarted modem to start with a clean environment and network connection. Only app running is Edge with a single tab for the Ookla speed test:

8:00am - speed test
936.9 down, 41.22 up, ping: 22ms

8:04 - start Teams Windows client. No active meetings or chats

8:05 - speed test
86.53 down, 41.10 up, 38 ms

8:08 - speed test
85.23, 41.23, 26 ms

8:11 - speed test
85.86, 40.90, 30 ms

8:13 - sign out and terminate Teams Client (no meeting or chats during up time)

8:13 - speed test
190.21, 41.22, 31ms

8:16 - speed test
937.90, 41.19, 27ms

8:18 - start Teams web client in second Edge tab. No meeting or active chats

8:19 - speed test
932.17, 41.23, 24ms

9:26 - speed test
942.49, 41.23, 35ms

9:28 - speed test
713.39, 41.13, 25ms

8:29 - start meeting in Teams web client

8:32 - speed test during active meeting
105.10, 41.17, 27ms

8:36 - speed test during meeting
79.71, 41.21, 30ms

8:37 - terminate meeting

8:45 - speed test
77.62, 41.02, 32ms

8:51 - speed test
85.67, 41.26, 22ms

9:00 - start new meeting
9:37 - end meeting
9:37 - sign out from Teams web client and close tab

9:38 - speed test
930.24, 41.31, 25ms

I can do more of these tests throughout the day. Just let me know what else you need.

Thank you!

best response confirmed by StaceeFrane (Microsoft)
Teams alone shouldn't be causing this type of substantial network drop for you, so this is definitely concerning. Do you have a ticket open with Support on this yet by chance? We might need to dive deeper into a netcap to understand what's really going on via the network and see what's taking away the chunk of your network here (Teams or other) in this case.

@Sam Cosby I don't have a ticket open, but can get one created.  Note that I have two surface devices; a Surface Laptop 2 (used for these tests) and a Surface Book 2 that has the same issue.  There's another post referred to earlier in this thread the seems similar and the poster also has a Surface device.  Maybe a coincidence but it's curious.

I have opened Case # 34167598 as suggested, with the O365 Support team.
I have the same issue, Do we have any solution?

@Martin_Grasso I went through a number of testing iterations with a Microsoft engineer and ultimately, nothing could be found.  I was able to reproduce it on two different Microsoft devices (SB2 and SL2), but could not make it happen on my wife's Dell laptop, or my mobile device with the Teams client active.  If you pursue it further and you do end up finding something, please post your results here as I would still like to know what's causing the problem.


Thank you!

How frustrating that a Microsoft engineer isn't able to solve this issue. I have also experienced the exact same issue, performing a speed test and very similar results. This has to be a known and tracked issue somewhere, but found very little on it, just this other post here:

Surely there must be more people having this same issue. I'm on a Virgin media connection in the UK, might this be implicated?
Hmm, just found this thread:
Which makes me start to wonder if the issue is at the router level. It seems there is a known issue with Hub 3 and Hub 5 routers even when in Modem mode when sending packets over UDP.
Going to speak to VM about an upgrade to my Hub

hi. same thing is happening to me. and I am using a macbook pro. Ever since I installed and log on to Teams, my network speed just crashed to 3mbps. I usually have 300mbps speed, especially on 5g wifi at home. 


I really need to get this fixed because I use Teams almost every day and other people at home using the same wifi connection are getting affected by the sudden slow internet connection


I can confirm this is also happening to myself. Laptop speed typically around 30mbps down. When I run TEAMS, that figure drops to around 1mbps. Very strange.

Took me a while to identify (only just figured it out today) which app was causing it, as my other devices or staff at my business are not experiencing the problem.

I have the same issues for some years now. I'm on a Dell laptop for work. My personal Asus laptop doesn't give these issues.

I tried debugging the situation for a long time and eventually found the Teams App was giving these issues. Tried clearing cache, rebooting laptop, rebooting WiFi but nothing works. When starting Teams App and start a meeting, after a few minutes all WiFi devices have low downloads and high ping. Only rebooting the modem resolves the issue.

It's probably some combination of modem, WiFi access point, Windows, Teams App, but it's for sure that when not using the Teams App, I have no issues and a very stable and fast internet and wireless MESH network.

I guess I just have to wait for another laptop and use Teams Web Client in the meantime.


Yep, I strictly use WebTEAMS now.

It's fine, does just a good a job as far as I can tell without the dramas.

1 best response

Accepted Solutions
best response confirmed by StaceeFrane (Microsoft)
Teams alone shouldn't be causing this type of substantial network drop for you, so this is definitely concerning. Do you have a ticket open with Support on this yet by chance? We might need to dive deeper into a netcap to understand what's really going on via the network and see what's taking away the chunk of your network here (Teams or other) in this case.

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