After I upgraded to Ubuntu 12.10,my browsers take long time (more than 15 sec.) for opening web sites or some times they don't open completely. But when site is opened once, the second time I open it loads faster.
Here is the video.
1) It could be your ISP's DNS. Try using Google's ones: 188.8.131.52 , 184.108.40.206
2) If that doesn't do the trick, try restarting your router.
3) You could also reinstall the firmware of your NIC.
4) For Firefox, type about:config on the url bar, write pipe in the search box, and enable network.http.pipelining