no, i used to have wpa personal, even when i tried WEP the speed improved, but only to around 30mb.
i set the channel to automatic, put it on WPA2 and changed the network key.
I dont see how that could have changed the speed, but thats all ive done.
its now running fine, but should it happen again.... i have not a clue how to fix it, just hope for the best with those settings should it happen again i suppose.