Dell XPS 13 Developer Edition Wifi Problem
I have a Dell XPS 13 Developer Edition (L322x) with the Atheros Killer wifi card installed. It's a lovely laptop, but the wifi was hanging for 30 seconds or so, or dropping and reconnecting frequently.
Solution 1:
After going down several blind alleys on various forums, I found the simple fix is to update the kernel. Open up a terminal (press CTRL+ALT+T) and type in:
sudo apt-get install linux-generic-lts-quantal
You'll be asked for your password.
Once the install has finished, reboot your laptop and all will be good.