Firefox is configured by absence for dial-up speeds. If you accept top acceleration internet admission such as DSL or cable, you can change a few settings in Firefox and access your download speeds. If you change the amount of access that Firefox uses to download, you will see a affecting increas in your bandwidth. The beyond the book you are downloading, the greater the acceleration will be, because added access can be fabricated to the server.

Method 1:

1. Change Firefox connection setting by typing “about:config” in the address bar of Firefox.

2. In the “Filter:” bar, type “persistent”

3. You should now see two preference names with their values:

network.http.max-persistent-connections-per-proxy user set interger 4
network.http.max-persistent-connections-per-server user set interger 2

4. Double click on each of the preference names. A window will pop-up allowing you to change the values for each. If you have cable or DSL use a number between 20 and 30!. Click OK.

Note: I use 26 for proxy and 26 for server

5.Restart Firefox and you will be able to download more files simultaneously and each file a lot faster.

Method 2:
Just install firefox extension, DownThem All and restart your firefox

Another good articles to speed up your firefox:

1. Speed Up Your Firefox by Adjusting Your HTTP Pipelining
2. How To Increase Firefox Page Transfer Speed Up To 40 Percent
3. revver videos how to speed firefox
4. How to increase firefox speed at yahoo answer