* Type “about:config” into the address bar and hit return.
* Type “network.http.*pipe” in the filter field, and change the following settings.
(Double-click on them to change them):
* Set “network.http.pipelining” to “true”
* Set “network.http.proxy.pipelining” to “true”
* Set “network.http.pipelining.maxrequests” to "8".
Helpful Links
http://egonitron.com/2007/05/25/the-truth-about-the-firefox-pipelining-trick/