I've always noticed that my wireless connection is a lot stronger in Windows XP than any version of Ubuntu. I have an inspiron 6400 with a broadcom BCM4311 (rev 1), and I'm currently using hardy. For example, tonight the connection has been very slow and has been dropping occasionally, but after rebooting to XP I haven't had any problems after over an hour. I'm very convinced that there is a significant difference between the two operating systems. Any ideas or fixes?

I came across this post from a while back which details the same problem, and with the same laptop:
http://ubuntuforums.org/showthread.php?t=388011