hi, this is to be expected and no indication of anything malicious going on. please see https://wiki.mozilla.org/E10s and https://blog.mozilla.org/futurereleases/2016/08/02/whats-next-for-multi-process-firefox/ on this subject.

philipp said

hi, this is to be expected and no indication of anything malicious going on. please see https://wiki.mozilla.org/E10s and https://blog.mozilla.org/futurereleases/2016/08/02/whats-next-for-multi-process-firefox/ on this subject.

ok, so how do I revert to previous version then?

you can disable e10s like this: enter about:config into the firefox address bar (confirm the info message in case it shows up) & search for the preference named browser.tabs.remote.autostart.2. double-click it and change its value to false and restart the browser. in the long run e10s will bring many stability, performance and security benefits - so unless you have any grave problems with it i wouldn't recommend disabling it...

Why revert to a previous version, Firefox has been known as a resource hog, but with Firefox going Multi-process I have noticed less lag when I have a frak ton of tabs open, compared to before the change. It also makes Firefox more secure eliminating certain types of add-on vulnerabilities. I would just leave it as is. But, that is just my opinion, your rig your choice. I will link some stuff if you still want to switch(if you haven't figured it out already.

https://support.mozilla.org/en-US/kb/install-older-version-of-firefox

or straight to the source

https://ftp.mozilla.org/pub/firefox/releases/

Corbul said

Hello! I'm a long-time Firefox user and I've noticed that after the latest (Januray, 2017) update there are two "firefox.exe *32" processes in my Task Manager. I wanted to know why? I googled this, and older topics (2014, 2016) said there can be a virus, but this never happened before, only after this update. Normally, the second process only takes up some 2000 to 30.000 kb, but now it takes as much as the first one (200.000+ kb). It's somewhat annoying because I really like Firefox but don't want it to turn into Chrome, eating up RAM and stuff. Please explain this to me, or fix it. Thank you!

You can inspect and modify the number of content processes via the dom.ipc.processCount pref on the about:config page if you do not want to disable multi-process.

See also the "Help -> Troubleshooting Information" page under Application Basics: Multiprocess Windows.

• http://www.ghacks.net/2016/07/22/multi-process-firefox/
• https://wiki.mozilla.org/Electrolysis/Multiple_content_processes

I have the same problem. TaskMgr shows 3 instances of Firefox running all the time, with the first two sucking up over 80% of the cpu. Firefox hangs for a long time at startup. Firefox will drastically slow down to a crawl when it's on a news-site (e.g. CNN) that has lots of video feeds and everything else that I'm running also hangs. See attached PDF with screen print.

Another support forum post (2 firefox.exe running in the background) identified the problem & contained a solution. The problem is Firefox's multiprocess (e10s) feature. Turning off this feature fixed the problem. CPU utilization has returned to normal. Firefox now runs with 10% or less cpu. And I'm a happy camper :-)

FYI - Microsoft Edge also has a similar multiprocess feature. However, it's multiple instances of its exe's suck up a fraction of what Firefox took up.

cor-el said

You can inspect and modify the number of content processes via the dom.ipc.processCount pref on the about:config page if you do not want to disable multi-process. See also the "Help -> Troubleshooting Information" page under Application Basics: Multiprocess Windows.

• http://www.ghacks.net/2016/07/22/multi-process-firefox/
• https://wiki.mozilla.org/Electrolysis/Multiple_content_processes

Cor-El,

Thanks for the additional info. I'd thought it was an all-or-nothing deal. I'll read the info in the links and see if reducing/limiting the number of instances will resolve the performance problems.

vj