I've got a USB-WLAN Dongle using the r8712u driver and the connection is ultra slow. NetworkManager tells me the connection speed is 150 Mb/s and the router shows me 11 MBit/s. Although the dongle should go up to 300 MBit/s. I've tested this with Ubuntu 12.10 and 13.04. Same problem. I already searched for solutions but I couldn't come up with anything, besides reading that this is a driver in early development stages.
So I'm basically searching for a workaround for the speed problems, like using another or more up-to-date driver. Any suggestions?