Why is FireFox so slow to initially load web sites, and then works fine?
The last two updates on FireFox, on my Windows 7 64-bit computer, is very, very slow to connect to web sites (20-30 or more minutes.) Once it does, it works fine. It loads quickly from the cache, and it seems to actually connect to some web sites in the first few seconds before the delay begins. The computer has no malware; using Windows firewall; virus software disabled without solving the problem; using Windows Defender. Other computers on the same home network are having no problems with FireFox.
The default of the pref network.http.max-connections has been increased from 30 to 256 in Firefox 6+ versions.
Try to decrease the value of the pref network.http.max-connections from 256 to 30 as used in Firefox 3 versions.