Thanks the pipelining settings are a lifesaver with facebook.
It does make a difference.
I also have a problem with tabs staying forever in the "loading" status even after most of the page is displayed (I have the tendency to open lots of tabs simultaneously)
I changed this:
network.http.keep-alive.timeout : 30
(or some other low value - default is 300)
I guess this more radical option:
network.http.keep-alive : false
could work too. I think this problem is due to some some kind of zombie connections.
PS: It works, i confirm. No more endlessly "loading" tabs.
And here are some memory-saving settings:
browser.sessionhistory.max_total_viewers : 0
config.trim_on_minimize : true
browser.cache.memory.enable : false