Open firefox and type 'about:config' in the address bar
Alter this settings: network.dns.disableIPv6 set this to true
network.http.max-connections Set this to 100
network.http.max-connections-per server Set this to 100
network.http.max-persistent-connections-per-proxy Set this to 100
network.http.max-persistent-connections-per-server Set this to 100
100 is a random higher number I chose to ensure that firefox isn't waiting on the connections, especially on pages with many image hosts, avatars e.t.c.