Firefox has always been a popular alternate browser, although its popularity has been declining a bit, since the launch of Chrome. It is the common experience of many a Firefox users, that the browser, over a period of time slows down considerably. It may take a lot of time to load during startup and the overall speed could also be effected.
Firefox has made considerable improvements in the browsers memory consumption and utilization – but it still makes people wanting more. In fact, some even prefered to install the Memory Restart or Memory Fox add ons from Mozilla – and even considered disabling the slowest Firefox addons. Speed Up Firefox
I do not normally use Firefox, preferring instead the Internet Explorer, but I do know of five freeware that may help you optimize Firefox and its memory and make it load and run faster.