Why are first connections slow and subsequent ones very slow or won't connect?
Since upgrading initial connections are often slow and subsequent connections very slow or won't connect. I have had to revert to Internet explorer which works fine!
Opaite Mbohovái (1)
The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.
You can try to decrease the value of the pref network.http.max-connections from 255 to a more modest setting like 30 as used in Firefox 3 versions.