The auto-update feature of Firefox put me into version 6 and I've had nothing but trouble with the incredible sloooooowness of forum pages loading. It made SOH browsing torture.
I tried Google Chrome, and was very impressed with it's quickness in both page loading and downloading... but I missed my old FireFox.
What I did was to remove Firefox with the windows control panel, then re-install an old copy of FireFox 4.01. It worked like a charm, and I can now speedily browse with my old comfort settings.
No one at FireFox seems to acknowledge the problem with the current version... and the version7 beta also has the problem.
So you can solve it by taking a great leap backwards... not exactly what Mao envisioned.