My clever fix might not suit you but I won't use the interweb without some adblocking. I use uBlock Origin with NextDNS.

This VASTLY speeds my experience.

https://addons.mozilla.org/en-US/firefox/addon/ublock-origin/

You will need to search for NextDNS as I cannot link to it. It is a free DNS service for adblocking. PLUS it works on your phone even not using wifi :)

I allready use uBlock Origin. Problem is that in the new Facebook page (after they changed the look) it block absolutly nothing because all URLs are at Facebook. Tried all standard filters, and tried making my own too. But nothing stops theis script that gets slower and slower (with Firefox warning after a while). Only hting that helps is closing Firefox and restarting (closing the Facebook "tab" does not help, so something is happing to Firefox). Is there something in the script enginge that leaks memory or somthing since it gets slower and slower?

PS! Feel free to post a list of what filters you use in uBlock so I can cross-check.

Also my own filters (mainly to work on norwegian pages) are here: https://firefox.osterud.name

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems.

Ummm... Problem is still here... Facebook slow up with or without uBlock Origin. Firefox eventually (when it gets too slow) shows a "script takes too long" warning. But still needs you clever folks out there to find a real fix for this slow Facebook