Cacher is the code snippet organizer for pro developers

Over time, I collected some options to make Firefox really fast.
 
WARNING! NO WARRANTY, use on your own risk!
 
If you know what you're doing, go to 'about:config' and edit the listed values accordingly.
Hint: Double-click boolean values to toggle true/false.
 
###########################

If mouse-wheel scrolling is slow, try

general.smoothScroll = false

############################

browser.display.show_image_placeholders             false
browser.tabs.animate                                false
ui.submenuDelay                                     0
network.prefetch-next                               true
network.http.pipelining                             true
network.http.pipelining.ssl                         true
network.http.proxy.pipelining                       true
network.http.pipelining.maxrequests                 8
network.dns.disableIPv6                             true
network.http.max-connections                        48
network.http.max-connections-per-server             16
network.http.max-persistent-connections-per-proxy   16
network.http.max-persistent-connections-per-server  8
content.notify.ontimer                              true
content.switch.threshold                            750000
nglayout.initialpaint.delay                         0
config.trim_on_minimize                             true
browser.sessionhistory.max_total_viewers            0
browser.cache.memory.capacity                       65536
(new Integer) content.notify.backoffcount           5
(new Boolean) plugin.expose_full_path               true
(new Boolean) content.interrupt.parsing             true
(new Integer) content.max.tokenizing.time           2250000
(new Integer) content.notify.interval               750000
 
###########################

More aggressive options:

network.http.pipelining.aggressive                  true