Firefox 56 and excessive memory usage (10+GB)

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Joined: June 23rd, 2009, 10:19 pm

Post Posted October 6th, 2017, 11:45 am

I have 16GB of RAM, and since updating to Firefox 56, I have noticed it wants to use most of it. I put my system to sleep instead of shutting down and generally leave Firefox running all the time. Previously, after 2+ weeks, Firefox never used more than 2-4GB, but now after a day or two, Firefox is using over 10GB.


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Post Posted October 6th, 2017, 12:48 pm

about:memory might provide some clues ? (but I am clueless as to how to make sense of what it shows).

Some are likely to say, does it happen if you restart in Safe Mode?
If that is feasible, that might be worth a shot.
If not, perhaps look into disabling all but "required" extensions & run for a while like that & see what happens.

Maybe reboot your computer.

Just yesterday, I had FF using 4-6-8 GB RAM, but more then that was 25% CPU usage (100% of 1 core).
It was running like crap.
RAM usage might not have been unexpected. (OK it was, but possible it was just because of what I had been doing?)
CPU usage, I could find no reason for.

Restarting FF, I was shortly back in similar situation.

Rebooting my computer (last time before yesterday was 144 days ago), seemed to have things running better.
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv: Gecko/20110420 SeaMonkey/2.0.14 Pinball CopyURL+ FetchTextURL FlashGot NoScript

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Post Posted October 6th, 2017, 4:43 pm

I rebooted two days ago when I saw FF using 12GB. When I made the OP, the system had only been up 2-days with Firefox running the whole time, and Firefox was consuming 10GB. The weird thing (at least for me) is that Firefox seemed to be running fine. It wasn't slow or eating up CPU. I had to open task manager to kill a locked up game and saw the high memory usage. I assumed it was the game, but after killing it, the memory usage didn't drop. That's when I saw it was Firefox. I rebooted after that.


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Post Posted October 7th, 2017, 2:12 am

Cold boot the machine using the Power Users menu which you'll see by right clicking the Start button. Shutting down the PC flushes the memory after which memory usage will return to normal.

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Post Posted October 7th, 2017, 2:53 am

Hello Same happened with me .

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Post Posted October 7th, 2017, 3:11 am

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Post Posted October 11th, 2017, 5:30 pm

Same thing is happening to me. It's been going on for months though, not just FF56. I'm so tired of it that I'm ready to get rid of it, and go to something else.

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Joined: October 13th, 2017, 1:35 am

Post Posted October 13th, 2017, 1:43 am

Same here - laggy page scroll; flash video stutters; and a merciless memory hog - keeps climbing and never releases it. Despite the dire warnings fm Mozilla re. downgrading had no trouble installing Firefix V55.03 over 56 without unistall - working great so far... Not happy about plugins I use being made redundant fm FF 57 either.

Old version installs here:

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