I have a laptop with dual boot elementaryOS Loki and Windows 10. Until recently everything was fine, but now suddenly the wifi in elementaryOS is extremely slow (~0.5Mbit download, most speed tests don't even start the upload test). With Ethernet, I get the normal 80 MBit download. I also tried it with Windows where it's still 25 MBit via Wifi.


lspci -knn | grep Net -A2
01:00.0 Network controller [0280]: Intel Corporation Centrino Advanced-N 6235 [8086:088e] (rev 24)
    Subsystem: Intel Corporation Centrino Advanced-N 6235 AGN [8086:4060]
    Kernel driver in use: iwlwifi

 uname -a
Linux tobias-530U3BI-530U4BI-530U4BH 4.10.0-38-generic #42~16.04.1-Ubuntu SMP Tue Oct 10 16:32:20 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
  • Welcome to U&L , what is the output of lspci -knn | grep Net -A2 and uname -a? you can edit here – GAD3R Nov 13 '17 at 17:19
  • added the info to the post – ghost in a jar Nov 13 '17 at 18:08
  • the iwlwifi module may be disabling wireless N, as described at: askubuntu.com/questions/119578/… – Tim Kennedy Nov 13 '17 at 18:11
  • I did that, its a little better now at around 6 mbit but signal strength is alot worse even if i'm sitting 2m from the AP EDIT: I tried 11n_disable=8 and now it's back to 40MBit, the wifi card can't do much more than that. Thank you! – ghost in a jar Nov 13 '17 at 18:29

To ameliorate the connection through the intel wifi card you can:

  • Disable 802.11n
  • Enable software encryption
  • Enable the transmission antenna aggregation
  • Disable bluetooth coexistence

Create a /etc/modprobe.d/iwlwifi.conf with the following content :

options iwlwifi 11n_disable=1
options iwlwifi swcrypto=1
options iwlwifi 11n_disable=8
options iwlwifi bt_coex_active=0

iwlwifi troubleshooting on arch-linux


TL;DR: it appears 4.17.x (and higher) kernels achieve high speeds with the iwlwifi driver with stock configurations.

I was also experiencing very slow wifi under Linux (Ubuntu 18.04LTS with it's stock kernel - 4.15.0-30-generic and 4.15.18-041518-generic) with stock configuration. My setup was capable of ~55MB/s in Windows 10, but only ~3MB/s in Linux. The card is an AC9260 in a Dell XPS 15 9570 if that's important.

I tried everything recommended elsewhere (power management, 11n_disable modprobe arguments, etc etc) and nothing worked. I reverted all those changes so my config was stock Ubuntu 18.04LTS post-install config.

I installed UKUU (an ubuntu kernel updater package, if you use a different distribution, you'll need another kernel upgrade mechanism), upgraded to 4.17.x-mainline (currently 4.17.14-041714-generic) and with no other changes I achieve 47MB/s in Linux now. My bandwidth tests are not scientific enough to say I couldn't get equal performance to Win10 now, but even in the absence of a git bisect to see what solved it, I consider this a solved problem now since a simple kernel upgrade works.

[edited 2019/01/30 to report I continue to have success with 4.19.x and 4.20.x series - it appears 4.15.x simply had a performance issue with this driver, fixed sometime on or before 4.17.x, and it has continued to be just fine since.]

  • Welcome on the Unix SE! – user259412 Aug 12 '18 at 21:09

My solution is to force my pc to connect to the 2.4GHz wifi channel instead of 5GHz. My wifi speed jumps to ~90 Mbps from 1 Mbps.....

To check which wifi channel your pc is connecting: sudo iwlist channel

To force your PC to connect to 2.4GHz wifi channel: you can set different names for your different bands on your router. or find other ways on your PC side.

More information about my case: Dell inspiron, dual boot (ubuntu 18.04.2 LTS, and windows 10) wifi with win works well; wifi with ubuntu is extremely slow; connect ubuntu to the hotpot of my cellphone, wifi speed works well (this gives me a hint to find the solution).


What worked for me was adding the line options iwlwifi 11n_disable=8 to /etc/modprobe.d/iwlwifi.conf

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.