Firefox About Config

Speed
network.http.pipelining true
network.http.pipelining.maxrequests 100
network.http.proxy.pipelining true
nglayout.initialpaint.delay Integer 0
network.http.max-connections 48
network.http.max-connections-per-server 16
network.http.max-persistent-connections-per-proxy 8
network.http.max-persistent-connections-per-server 6

Custom
browser.search.openintab;true
browser.tabs.loadDivertedInBackground;true

References: Firefox Extension