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Firefox causes 100% CPU usage when opening couple tabs at the same time!!!

  • 21 iimpendulo
  • 1 inayo le ngxaki
  • 11 views
  • Impendulo yokugqibela ngu empleat

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I Am on desktop:

i5 9600KF (high performance mode) 16GB 3200mhz ram NVME... Windows 10 Pro x64 Firefox last stable

When I open Firefox tabs aren't loaded all at the same time, but they are suspended. So after that: when I switch between 6 tabs quickly - they start to open at the same time. And CPU usage skyrockets to 100% LOL! Given I Am on high end PC - this is joke! I was using chrome and had hundreds of tabs and Chrome doesn't even suspend them by default. They open all at the same time I think!

So there is something wrong! I tried troubleshooting mode and it was the same problem!

Thanks for help!

I Am on desktop: i5 9600KF (high performance mode) 16GB 3200mhz ram NVME... Windows 10 Pro x64 Firefox last stable When I open Firefox tabs aren't loaded all at the same time, but they are suspended. So after that: when I switch between 6 tabs quickly - they start to open at the same time. And CPU usage skyrockets to 100% LOL! Given I Am on high end PC - this is joke! I was using chrome and had hundreds of tabs and Chrome doesn't even suspend them by default. They open all at the same time I think! So there is something wrong! I tried troubleshooting mode and it was the same problem! Thanks for help!

All Replies (20)

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I tested by visiting every tab in this window, 14 of which hadn't been loaded yet after the Firefox 92 update. CPU use went to 100% for maybe 10-15 seconds, and then returned to baseline. Here's the graph:

Of course, the strain probably depends on the specific pages involved, but I'm not getting a hair-on-fire three-exclamation-point feeling about this.

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[quote] But I'm not getting a hair-on-fire three-exclamation-point feeling about this. /quote

What do you mean? This is not normal, 6 tabs shouldn't load so slowly and shouldn't max whole i5 9600KF!!! I used to open on Chrome hundreds of tabs at start and it took just couple seconds... 6 youtube tabs BTW.

Ilungisiwe ngu empleat

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Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?


https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding

https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster

https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix

https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram

https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

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empleat said

This is not normal, 6 tabs shouldn't load so slowly and shouldn't max whole i5 9600KF!!! I used to open on Chrome hundreds of tabs at start and it took just couple seconds... 6 youtube tabs BTW.

How slowly? It's possible that Firefox can't load YouTube from cache and needs to retrieve the pages again. I generally don't keep YouTube tabs open, so I don't have a reference point for that, just the test results I gave you.

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FredMcD said

Start Firefox using Troubleshoot(Safe) Mode {web link} A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there? https://support.mozilla.org/kb/Firefox+is+already+running+but+is+not+responding https://support.mozilla.org/en-US/kb/firefox-slow-how-make-it-faster https://support.mozilla.org/en-US/kb/firefox-uses-too-many-cpu-resources-how-fix https://support.mozilla.org/en-US/kb/firefox-uses-too-much-memory-ram https://support.mozilla.org/en-US/kb/firefox-hangs-or-not-responding

As I said: I tried troubleshooting mode already - same problem :(

jscher2000 said

empleat said

This is not normal, 6 tabs shouldn't load so slowly and shouldn't max whole i5 9600KF!!! I used to open on Chrome hundreds of tabs at start and it took just couple seconds... 6 youtube tabs BTW.

How slowly? It's possible that Firefox can't load YouTube from cache and needs to retrieve the pages again. I generally don't keep YouTube tabs open, so I don't have a reference point for that, just the test results I gave you.

Extremely slowly: it takes couple seconds. Besides even single tab cause CPU usage go to 80% and loads like 3 seconds.. While 6 tabs like 6 seconds.

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Maybe it's this bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1724980

Can you try to test it in the Nightly version?

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On nightly usage is slightly less: 60-80% but tabs open still slowly!!! What is that bug BTW? I don't see solution there!

Ilungisiwe ngu empleat

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92.0.1 problem still exists, any ideas ???

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Hi empleat!

How many browser extensions/add-ons do you have? Can you list them? Many interact with YouTube so it's possible one is the culprit.

Side note: I'm not surprised YouTube links are loading more quickly in Chrome. Google owns both and I have a feeling YT is integrated into Chrome by default (aka, it preloads video DLLs). This is all speculation though, I haven't tested.

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RoyDA said

Hi empleat! How many browser extensions/add-ons do you have? Can you list them? Many interact with YouTube so it's possible one is the culprit. Side note: I'm not surprised YouTube links are loading more quickly in Chrome. Google owns both and I have a feeling YT is integrated into Chrome by default (aka, it preloads video DLLs). This is all speculation though, I haven't tested.

Nope that's not it! I tried nightly build = same issue, also clean boot, start Firefox in troubleshooting mode, general tips on Firefox support site for high cpu usage, safe mode networking. No background programs! I Am now on FF 92.0.1 - same issue!

Slowness is not exclusive on youtube unfortunately and tabs load very slowly, just 6 tabs maxes CPU on 100% while they load slowly....

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Can you post a comparison screenshot of the Windows 10 Task Manager Performance tab showing the performance with restoring your tabs? For reference, mine was attached to this reply: https://support.mozilla.org/en-US/questions/1349711#answer-1441369

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Thanks. Looks like about 15 seconds of higher CPU utilization to restore 6 tabs with a brief spike to 100%. With my slower system, restoring 14 tabs caused a much longer spike to 100%.

I don't know what is involved in restoring a tab, so I don't have an opinion on whether this is reasonable. Do you want to file a bug report? https://bugzilla.mozilla.org/

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Yeah probably should do that. zzzzzzzzz...

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jscher2000 said

Thanks. Looks like about 15 seconds of higher CPU utilization to restore 6 tabs with a brief spike to 100%. With my slower system, restoring 14 tabs caused a much longer spike to 100%. I don't know what is involved in restoring a tab, so I don't have an opinion on whether this is reasonable. Do you want to file a bug report? https://bugzilla.mozilla.org/

Bugzilla says: it is not a bug, after checking a profile record. Hmmm... It is strange, because I Am using 2 Mozilla instances, it was happening in both (including one with small amount of tabs) but now since v 93.0, it doesn't happen there. However it is still happening in my main instance! But even in instance, when it doesn't max CPU to 100%, 6 tabs cause still 53% CPU usage, which doesn't seem great, at least they load instantly!

Ilungisiwe ngu empleat

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Now issue doesn't happen with only 6 tabs in my main window, while it was previously happening in 3 different profiles of Firefox! That is after Firefox 93.0. But performance in my main windows where I have 800 tabs is still piss poor. It used to be fine with 1000 tabs... So I Am leaving Firefox, I can't work like this sadly...

Ilungisiwe ngu empleat

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Part of the problem may be your internet service provider. Opening multiple tabs can create an overload on your downloaded data via the ISP, especially if you use satellite service.

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How would that be related to 100% CPU usage, besides I have 150mb/s cable! Never had problems with my ISP over 10 years!

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My apologies for attempting to help. It won't happen any more. Have a great day and good luck.

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Bud said

My apologies for attempting to help. It won't happen any more. Have a great day and good luck.

LOL you are crazy. I merely said that is not problem. OK I will lie and talk to you next hour about imaginary problem. What Am I supposed to say.

Today people are so sensitive, we are just talking facts... I don't understand what is going oN?

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