If your Firefox is sluggish on on Ubuntu 10.04 this might help.
Fire up Firefox and type “about:config” in the URL bar. That will bring up the config page.
Search for the lines below and change them accordingly to reflect the changes below.
`- network.http.pipelining > Make it True
- network.http.pipelining.maxrequests > Make it 8 or 10
- network.http.proxy.pipelining > Make it True
- network.dns.disableIPv6 > Make it True`