When I use my wifi usb stick (TP-Link TL-WN722N) on Ubuntu 14.04 I only get very low download speeds (around 3,5 Mbit/sec). When I reboot to Windows I get the full 25 Mbit/sec that my internet connection is capable of.
I have also tried Crunchbang 11 Waldof, but there too I only get 3,5 Mbit/sec download from the wifi usb stick.
Also, I am not the only one with that problem:
http://www.techques.com/question/24-111214/Slow-Wireless-With-TP-Link-TL-WN722N-Wireless-USB-Adapter
Slow wifi download speed with a TP Link tl-wn722n
The only thing that people are suggesting is disabling hwcrypt:
echo "options ath9k_htc nohwcrypt=1" | sudo tee /etc/modprobe.d/ath9k.conf
However, that doesn't change anything for me.
Could this be a bug in the ath9k driver or the firmware (htc_9271.fw)?
Best Answer
All right, looks like I found a solution: I tried using laptop+TP-Link TL-WN722N with another router and suddenly the wifi stick was able to deliver the expected performance.
In the end I managed to narrow it down to a setting of my router called "WMM" (also called Wifi-Multi-Media or Wireless-Multimedia-Extensions or WME).
If I disable WMM in my router, the wifi stick delivers the expected 25 Mbits/sec that my internet connection is capable of.
However, please note that if you disable WMM/WME in your router settings your router will reduce its wifi speed to 54 Mbits/sec (IEEE 802.11g).
Summary:
On Windows the TP-Link TL-WN722N works as expected.
On Linux the TP-Link TL-WN722N only works correctly with IEEE 802.11g. If your TP-Link TL-WN722N is slow, you need to disable WMM or WME in your router settings.