Here is an old trick used by many peoples... Well it worked for me but not a big diffrence... i think it depends on PC.
here it goes.....
1. Typa about:config in the url bar in Firefox.
2. Type network.http in the filter bar.
3. Double click on network.http.pipelining to set it as true
4. Set network.http.pipelining.maxrequests to 30 (Firefox will then make up to 30 requests at a time)
5. Set network.http.proxy.pipelining as True
6. Rightclick anywhere and choose New -> Integer, name it nglayout.initialpaint.delay and make the value 0.
7. Restart Firefox