I've was having the same problem on my dell 2650 laptop, but after running iwconfig <ifname> rate 54m and turning off cts protection on my AP, i was able to get download speeds of over 6MB/s using the speedtest at http://www.speakeasy.net/speedtest/. when looking at dmesg | grep <ifname> i noticed the interface is flapping between long and short preamble, but it doesn't seem to have an affect on the connection speed or reliability.
I've was having the same problem on my dell 2650 laptop, but after running iwconfig <ifname> rate 54m and turning off cts protection on my AP, i was able to get download speeds of over 6MB/s using the speedtest at http:// www.speakeasy. net/speedtest/. when looking at dmesg | grep <ifname> i noticed the interface is flapping between long and short preamble, but it doesn't seem to have an affect on the connection speed or reliability.