Comment 13 for bug 378156

I've been running stock Ubuntu 9.04 on an EEE 701 with an AR242x adapter and seeing similar problems. iwconfig reports almost constant changes (changing several times per second) to the bit rate on the wlan0 adapter when connected to an access point in the same room, with the values ranging from 1 Mb/s to 36 Mb/s. Link quality and noise level values stay the same throughout.

Installing the backported drivers in the linux-backports-modules-jaunty package appears to resolve the issue; the bit rate remains near-constant at either 48 or 54 Mb/s (with a much slower rate of change), signal strength is comparable to other wireless-enabled computers I have available that use the same access point, and download speeds are consistently good (I can download a 900 MB file over HTTP from a local server at a constant rate of 3 MB/s) and without apparent episodes of packet loss.

If it would help, I can revert back to the stock driver and provide whatever debugging information is required, but based on my experience, I'd suggest simply trying to get the relevant driver(s) into an update.