Firefox is the most popular and widely used browser as far i know, but not every user like me got high speed internet so for them here i'm gonna let u know some easy tricks...
Like most other browsers Firefox also send request to a server then wait for the response before continuing. There's a aggressive technique which let the browser send multiple requests befire any of them are received ,sometimes reducing page download times. Its called pipelining .Type about:config in the address bar then double click network.http.pipelining and network.proxy.pipelining so that their values are set to true, then double click network.http.pipelining.maxrequests and set it 8.
For your information, some servers dont support pipelining so if u regularly visit these then the tweak can reduce perfirmance. If u dont fing it useful or problems then set network.http.pipelining and
network.http.proxy.pipelining to false again.