Under different version of Linux Fedora box, I’ve noticed that Firefox is far slower than under Windows box.
After some googling, a suggested solution is to disable the IPv6 option
Under firefox: type “about:config” in a new tab as a URL address.
Then, search for network.dns.disableIPv6 and set it to True. It was false on mine.
After that, the web page upload as much faster.
This was true under Fedora 8 and 9. Now, under Fedora 14, I got the same issue but this trick did not work.