That's right. It gets worse for people who have the unfortunate habit of using multiple content blockers, not better. The undue memory usage will also be higher when enabling more filter lists. For you it's enough to use uBlock Origin only.

For real the Windows Task Manager screenshot doesn't say anything helpful. Try to open about:processes page, at least it shows where memory goes.

Thank you for the feedback. Just FYI One instance of Firefox today reached 3.2Gb of memory and shortly thereafter crashed, so Firefox clearly has a problem dealing with add ons that protect a user from unwanted data wasters and unwanted content push systems.

I will try disabling some options, and report back further with the info you requested

If Firefox browser is crashing because of Addons then that would mean Firefox browser isn't the problem but the Addon. If you disable all Addon and turn on/off each at a time to verify they aren't the cause as well to narrow down the issues. As mentions using too many adblocker will also cause problem as they will hamper each from working properly as well. You need only a single good adblocker that fits what you want. And make sure not to run too many A/V software as that can also cause issues with sites as each blocks the other or let's malware/virus get through to the computer.

Thank you markwarner22. As I mentioned to TyDraniu, I systematically went throug all the Addons and found Ghostery to be the problem. This has now been removed and all others seem to be playing well together. Thank you all for your advice.