Simple changes to ‘about:config’ to speed up Firefox
Type about:config in your address bar (you may get a message asking if you really want to do this – just answer yes).

Now type browser.history in the filter. We’re looking for three entries:
Right click on browser.history_expire_days and choose Modify. Change the value to either 7,14,28 or 56 (I choose 56 just to test it).
Now, right click on browser.history_expire_days_min and again choose Modify. Change the value to 7, 14, 28 or 56 as before (I choose 7 to test it).
And lastly click on browser.history_expire_sites. The default value is set to 40,000. Right click and change the value to 1000.
Restart Firefox for the changes to take effect.
To ensure optimization check the SQLite database. Instructions can be found at WebUpd8.
H/T gHacks

I believe it helped…thanks.