If you think that your firefox is slow you can try the following tweak to fasten it.
Note:- Try this only if you are an expert.
- Type about:config into the address bar and hit enter.
- A warning sign will appear, click continue.
- Scroll to the entry- "network.http.pipelining" - Change the value to "True" by double-clicking it.
- Scroll to the entry- "network.http.proxy.pipelining" - Change the value to "True" by double-clicking it.
- Scroll to the entry- "network.http.pipelining.maxrequests" - Change the value to "8" by double-clicking it. Not more than 8, because 8 is the max value allowed.
- Now, right-click anywhere and select New >> Integer., name it nglayout.initialpaint.delay and set its value to 0?. This value is the amount of time the browser waits before it acts on information it receives.