Visitor

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7 Messages

Saturday, May 9th, 2026 3:30 AM

Slow speed on Linux laptop

I am having the same problem as the linked threads. My internet speed on my Linux computer ranges between 6mpbs and 12mpbs. This is ONLY the case on my home network. I have run through every Xfinity troubleshooter, changed Linux distro, and replaced my computer's WiFi chip. The speed was great up until very recently.

https://forums.xfinity.com/conversations/your-home-network/extremely-slow-link-speed-54mbitss-on-linux-laptop-with-2gig-plan/69e9bef8a857df5bf3fc95fb

https://forums.xfinity.com/conversations/your-home-network/slow-download-speed/69dc707221e4e9620a17eb89

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Official Employee

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2.5K Messages

3 days ago

Thanks for reaching out @phiboy! I completely understand wanting to see speeds above 12 Mbps. A step you can try now if you haven’t already is connecting your laptop directly via an Ethernet cable (CAT6 or higher) to the modem or gateway and run a speed test. This helps confirm whether the issue is strictly WiFi related or affecting the connection overall. 

 

Was the WiFi chip replaced before or after your started to experience slow speeds?

Visitor

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1 Message

1 day ago

I am actually experiencing the same thing. I connected my linux laptop to another ISP at my grandparents house and it worked flawlessly. I have troubleshot my issue and determined that it is due to the automatic wifi settings on the xfinity router setting the width to 20. Plugging into ethernet works but is not ideal for the laptop. I could easily change the settings in the admin portal were they not locked due to "automatically" being managed. Is there anything else that I can do?

Visitor

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7 Messages

Where can you see the width?

Visitor

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7 Messages

And which distro are you on? Just trying to find if there's some commonality between those of us having this issue.

Visitor

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1 Message

1 hour ago

I have the exact same issue. 12-20 mbps on wifi, ethernet works fine. I get the kernel message "required MCSes not supported, disabling HT".  My iw dump shows tx and rx bitrate of 54 MBit/s no matter what I have tried, and i tried a lot of things!

* Fresh Linux install.
* Different desktop environments.
* Reconnecting repeatedly.
* Full NetworkManager + wpa_supplicant state reset.
* Recreating Wi‑Fi profiles.
* Power-save checks.
* USB adapter
and more

Nothing works. Please fix!

Visitor

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7 Messages

What distro are you using?

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