How to fix slow wireless on machines with Intel wireless cards?

I have looked through all the previous questions but turning power management off for the Wi-Fi card didn't work. This problem seems to be with the Lenovo Thinkpads. I switched to Ubuntu 11.10 from Windows 7 3 days ago so I'm new to the operating system.

Solution 1:

OP Posted:

• Note1: The slow connection can be due to your service provider or any other reason, to check it, try the same network by any other computer with different OS or by connection to the network by a cable. If it is fast, this solution can help you. If not, it can be wasting of time!*

• Note2: In the first link in the References I put, there are more methods to solve the slow wireless connection. Each method solves different possible reason of the slow connection. I recommend to test the solution I put here before searching for different methods because it is most probably effective.*

If you are using Ubuntu 11.10, do the following:

open terminal. Type the following two lines:

sudo rmmod -f iwlagn
sudo modprobe iwlagn 11n_disable=1

Now, check your wireless Internet speed. If it is still slow, this solution is probably not a solution for your case. In this case, just restart the computer to revert the change you did. If it becomes normal and fast, do it permanently by typing the following line in the terminal:

gksudo gedit /etc/modprobe.d/iwlagn-disable11n.conf

A file will be opened. At the end of the file, paste the following line then save:

options iwlagn 11n_disable=1

After saving, just quit, and ENJOY!

Solution for Ubuntu 12.04:

open terminal. Type the following two lines:

sudo rmmod iwlwifi
sudo modprobe iwlwifi 11n_disable=1

Now, check your wireless Internet speed. If it is still slow, this solution is probably not a solution for your case. In this case, just restart the computer to revert the change you did. If it becomes normal and fast, do it permanently by typing the following line in the terminal:

gksudo gedit /etc/modprobe.d/iwlwifi-disable11n.conf

A file will be opened. At the end of the file, paste the following line then save:

options iwlwifi 11n_disable=1

After saving, just quit, and ENJOY!

References:

• http://www.unixmen.com/resolve-slow-connexion-when-using-wifi-in-ubuntu-1104-natty-narwhal/
• http://ubuntuforums.org/showthread.php?t=1965970&page=2

*I tried both solutions and they work.

Solution 2:

I solved this for myself by using the instructions here.

in a terminal, write:

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

For 12.04 and newer: change options iwlagn 11n_disable=1 to options iwlwifi 11n_disable=1