Does anyone have this issue were firefox becomes slow if left open for a long time. In my case after a couple of weeks rendering becomes slow and when I use youtube for example if is laggy, just trying to change volume taka few second to show the volume bar. It also happens to my laptop at work. I have around 30 tabs open.
Under
about:unloads, you will see a list of open tabs, sorted by resource usage. You can click-spam the “Unload” button until that list is empty, or until the most resource-intensive tabs are off the list.This does not require any third-party dependencies, and the tab will still be present on top. The site will reload once the tab is selected again.