I recently installed a new distro on my netbook. After using it for a few seconds I knew something was wrong with the wireless connection as it was hell’a slow. Could not figure it out at first but then I saw what I was missing: It was only slow while running on battery.
Turns out it was the power management. Whenever I went over to battery it kicked in and my ~3MB/s speeds went to ~32KB/s. Big, big drop so something must be done, right? Right.
iwconfig wlan0 power off
Then make it executable with
chmod +x /etc/pm/power.d/wireless.
This will disable wireless power management whenever the machine goes to battery power. Problem solved.