Ok, here is the "fix". (workaround.)
This is more of a GNOME issue.
Load KDE (the other GUI) and run your browsers their.
It works much faster. (The pages load much, much, better.)
Personally, KDE is much better for a newbie. I am already starting to like it.
Install KDE from the Add or Remove Applications -- > KDE. Then from the GNOME login click Session, and then select KDE.
The GUI is a bit different, but I think you may actually find KDE much more likable for a newbie.
Next, so anytime you login to your desktop in the future, go to the terminal and type:
password: enter your super user (root) password
If perhaps you don't have gedit, use something such as VI or emacs.
(Like I mentioned, I am a newbie, too. I like to use graphical tools -- then learn the commands.)
Then change the value of DESKTOP="GNOME" to DESKTOP="KDE"
Save that, log out (restart -- not needed) and log back in.
You should be logging back in via KDE without selecting the session.
Try running Firefox.
Much faster, eh?
Also - I'd suggest updating to the latest edition of Firefox and removing the present one. (At least that's what I did.)
Tell me if this helps.
I don't need donations or anything, just people telling me I helped -- that's all I enjoy!