Firefox -- improving performance
Some people have found firefox runs slowly. Often one cause is that the default is set to use IPV6 .
Set an option network.dns.disableIPV6 to TRUE --default is false.
Most ISP's still use the old (IPV4) system. You will still of course be able to access the new sites.
There are a whole slew of other options as well.
To get these "Hidden Options" set the browser address to about:config
Hope this helps