Hi Sebastian, Someone had a very long running thread * on this. We never got to the bottom of this properly. A couple of important points to remember are

• FaceBook has very complex scripts and potential to use a lot of memory.
• It may be difficult to tell what is actually a memory leak and what would be relatively normal or expected.

The thread in question was resolved because at present the problem does not exist in some pre-release versions of Firefox (Fx50). The solution to your problem may be to either wait a few weeks for such a version to reach Release or try it out now as an additional Pre-Release browser.

I note you are already using 64bit Firefox on Windows (32bit Firefox is still standard on 64bit Windows - unlike Linux where 64 bit Firefox has been used for years). That should handle large amounts of memory without the inherent limitations of the 32bit versions. As for it slowing Firefox down again changes in the pipeline may help here. Firefox is going multi process.

As a test I suggest you install Firefox Developer Edition or Beta. The DE will install as a separate additional browser with its own Firefox profile (Beta is a bit more tricky to install). Developer Edition is probably also multi process by default when installed.

• https://developer.mozilla.org/Firefox/Developer_Edition
• Or https://www.mozilla.org/en-US/firefox/channel/#beta
• What’s Next for Multi-process Firefox
  https://blog.mozilla.org/futurereleases/2016/08/02/whats-next-for-multi-process-firefox/
  

* Firefox crashes daily in plugin container on Facebook 

Oh ok, well it's not computer hardware related since this problem only started since FF X64 version 48.

Before that my RAM was hardly used, well let's say with lot's of tabs open maybe a gig. Now if I just open facebook and don't even do anything the memory slowly get's drained to maximum and than like I said the whole things crashes.

I will change to chromium for a while as primary browser and check now and than if Firefox is repaired. I have been waiting on a solution since version 48 and submitted multiple crash reports,...

You need to let us have the Crash IDs or file a bug yourself to stand a chance of getting attention. I5t is good to file crash reports but only some a fraction are even processed and then they need prioritising there are limited resources.

If it is a genuine memory leak from Facebook with Firefox then because it is a very popular site and especially if it causes crashes it is something developers would probably investigate, but it would need effort on your behalf to gather the data needed. Developers would probably only be interested if Firefox is run in a clean profile with no addons or plugins active and there are memory reports from about:memory and the related Crash IDs.

Also before considering embarking on such a cause check out at least Firefox 50. If the issue is already fixed in Fx50 it is pointless trying to file a bug because the problem is fixed, it just takes time for it to work its way in to the Release.

Your problem with facebook may not be the same as the issue in the other thread.

Have you seen

• Firefox uses too much memory or CPU resources - How to fix
• Troubleshoot Firefox crashes (closing or quitting unexpectedly)

Oh ok, well I'm using chromium now and that works without a issue with the same add-ons.

I don't see a reason to go try things out, chromium is even faster in loading webpages.

Thanks for the effort and letting me know how the report a bug system works.

I guess people can better just get another browser than wait for things to get solved in most cases, ...

Thanks for reporting this and then posting back. Good look with Google Chrome.

• Note Export Firefox bookmarks to an HTML file to back up or transfer bookmarks

I notice so far there is only one other person apparently voting as having this issue. (And that could be a false positive with the forum software assuming I have the issue becase I am posting in the thread.)

Yes sure it is your choice. We do not have the massive resources of Google. Whatever the problem you do have on facebook with Firefox it is probably not affecting everyone, or we would have been deluged with reports it should have shown up in

• These forums
• The Feedback reports from the help options
• Crash reports.
• Telemetry from those that have it enabled

Whatever the issue is it may be some sort of edge case that affect people with for instance specific combinations of software.

I am having a similar problem, I come back to my computer and it is using 8 gigs of memory in plugin-container, I checked the memory and it was all free allotments: 8,388,607.94 MB (100.0%) -- address-space ├──8,387,753.81 MB (99.99%) ── free(segments=452) └────────854.13 MB (00.01%) ++ (2 tiny)

The thing is that there is no way to clear the memory in plugin-container without killing the task. I do have 24 gig of ram, but this still makes the browser very unresponsive, like thirty seconds to do anything, and it appears to be related to something going on in Facebook.

I am running 49.02 x64, with no add-ons, plugins, extensions enabled or installed, and I do not have flash installed either.

Windoze 7-64bit, dual-quadcore xeon, 24gig ram.

I will gladly upgrade to 50 if you think it will help, where do you find the experimental versions these days?

Interesting, just had the same issue with 50.0 (x64), everything got really slow and I checked task manager and the second firefox task (used to be called plugin-container) was taking 9 gig of ram, and rising rapidly, I killed the second process and it reset everything and was fine again.

In Fx439 what was using plugin-container if you have no Flash Player ?

In Fx 50 it is going to be using multimode. That could increase CPU and memory use but the intention is for it to be (much) faster. You could try turning that on and off to see if it makes a difference.

With your 24GB ram and a hi spec cpu it seems odd it is

  very unresponsive, like thirty seconds to do anything, 

Facebook apparently uses many and complicated scripts I wonder if for instance you have script or add blocking, or maybe security software fighting with Facebook and slowing things down.

Presumably you tried the buttons in about:memory to see if they would knock back the memory allocation without killing a task.

The Firefox Developer version is pre beta but stable enough for me to normally use it as a day to day browser. Its only real disadvantage is it updates frequently usually daily. By default it installs with its own profile as a separate browser. Its main advantage is having the latest features and built in tools.If you are getting 30 seconds of jank it should be able to help in investigating that. You said

 I killed the second process and it reset everything and was fine again.

If it turns out facebook has issues with compatibility with multi process Firefox that is potentially going to be a serious issue that Firefox Developers will need to investigate, however with the popularity of Facebook, it would be odd such a problem has not already been identified. You would probably be best starting a new question thread of your own.

Unfortunately the last long Facebook thread ended badly, the problem appeared to have been resolved in a pre Release version of Firefox, but still existed when the particular Pre Release version became the Release.

I also note you mentioned

was taking 9 gig of ram, and rising rapidly

From a troubleshooting and investigation point of view that may be good in that it should help identify what is going wrong if the problem is obvious and easy to reproduce.