I've been reading about a lot of people having trouble getting their RT2500-based card to stay at 54M... Their speed is fine and normal for a while, and then suddenly slumps down to < 200 kB/s; iwconfig reveals that the rate is set to 1M, and manually setting it back to 54M temporarily fixes the issues.
But this seems to be an issue with older versions of the driver; I'm running Karmic and my rate is always 54M... I do experience the same symptoms though.
The only thing I can do is disconnect from the wireless network and reconnect; transfers jump back to max speed (1.2MB/s) instantly. Wired connection doesn't suffer from this issue, nor does Windows XP.
Any idea how I could diagnose this?
Thanks in advance!