If you are using Mozilla Firefox and find it slowing down over period of time, then you can free up some memory to speed it up.
about:memory is a special page within Firefox that lets you view, save, load, and diff detailed measurements of Firefox’s memory usage. It also lets you do other memory-related operations which are better explained on this page.
If you wish to free up some memory in Firefox, type
about:memory in the Firefox address bar and press Enter. On the next page click on “Minimize memory usage” under “Free memory” to free up memory.