Ubuntu – Slow WiFi since updating to 18.04


I've had some weird internet issues since upgrading.

First of all, my wifi USB dongle stopped working so I thought it was broken, I replaced it and was getting speeds of under 1 Mbps.

Since then I have had very poor download speeds, and surfing has been a bit hit and miss with some sites loading instantly, and others crawling. everything was fine using the same hardware on 16.04

What can I do to speed things up?


Best Answer

I just fixed this on ubuntu 18.04 - turns out there is some kind of issue with 802.11n and iwlwifi Intel chips. The solution is to turn it off.
Check if it works first with:

sudo modprobe -r iwlwifi

sudo modprobe iwlwifi 11n_disable=1

Make it permanent with this command:

echo "options iwlwifi 11n_disable=1" | sudo tee /etc/modprobe.d/iwlwifi.conf

I did this and my wifi speeds instantly went back to normal.

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