About:Addons-memory is a very handy addon for Mozilla Firefox that allows users to find out which particular addon is causing problem for the browser. After the installation (no restart required), all you have to do is to open a new tab and type “about:addons-memory” (without the quote) in the address bar. It will show you the summary of all the installed addons and their memory consumption. The Memory column shows the memory consumption of the specific addons (in MBs) followed by the addons column that shows the memory consumption in percentage.
The list is organized in descending order, starting with the addon that consumes the most resources. It is a pity that the list is not updated real-time, so you have to refresh the page to get the latest information. However, if you are constantly seeing a particular addon at the top of the list (other than the Firefox, which will always be the first in the list), you might want to remove it from the browser. About:Addons-Memory is probably not an addon that you will use it everyday or every moment, but if you are troubleshooting your Firefox and wondering what is slowing it down, this addon will be very handy. About:Addons-Memory for Firefox