Some users report their Firefox browser is scoffing CPU power
(2025/08/13)
- Reference: 1755073808
- News link: https://www.theregister.co.uk/2025/08/13/firefox_ai_scoffing_power/
- Source link:
People are noticing Firefox gobbling extra CPU and electricity, apparently caused by an "inference engine" built into recent versions of Firefox. Don't say El Reg didn't try to warn you.
Mozilla, in its finite wisdom, embedded LLM bots into recent versions of Firefox for the vitally-important purpose of… naming tab groups . Now, some users are [1]noticing CPU and power usage spikes caused by a background process called Inference . All we have so far is a smoking gun, but it does look like Mozilla's product management has maintained its laser-like aim at its own feet.
This looks like an unfortunate sequel to a series of recent stories from The Register . First, in March, we reported that [2]Firefox had built-in vertical tabs . In the second screenshot in that story, you can see something that reminded us of the wisdom of [3]Douglas Adams and John Lloyd : a quietly terrifying [4]ely of looming "AI" integration into Firefox.
ELY (n.) – The first, tiniest inkling that something, somewhere has gone terribly wrong.
The worrying sign to which we are referring here is the first button in the group at the bottom of the tab sidebar: AI chatbot . As soon as we found it, this vulture immediately [5]disabled it . The Irish Sea wing of Vulture Towers is a proudly and resolutely LLM-bot free zone.
Due credit to Mozilla here: this chatbot integration is easy to turn off. You can do it via the GUI – it's on the Settings screen behind the last button, ⚙️ Customize Sidebar . The first option in the section headed Firefox tools is AI chatbot . Untick for instant relief.
[6]
It's not just us. Quite a few users are asking for this, with pleas such as [7]Remove Firefox "AI Chatbot" Feature or [8]how to remove AI from my Firefox? or [9]Please keep AI out of Firefox .
[10]
[11]
Even so, it's metastasizing.
In April, we reported on the new [12]Tab Groups feature in Firefox 138 – although at the time we noted that we didn't seem to have it in our copy yet, presumably due to Mozilla's "phased rollouts" which means that new features aren't immediately enabled for all users. Mozilla has [13]instructions on how to use them , either by drag-and-drop or context menus.
[14]
Then in July we [15]reported on the next installment : Firefox 141 now has an odious new feature Mozilla dubs [16]AI-enhanced tab groups , to which the company adds a box called Things to keep in mind –
Firefox uses a local AI model to read your open tabs' titles and descriptions to suggest more tabs and group names. Everything happens on your device.
What an inspirational use of technology, to relieve the insufferable burden of thinking of a single-word name for an ephemeral group of web pages! However did we live without the guiding hands of these [17]machines of loving grace ?
To be fair – we are obliged to – it's not yet certain that this is the issue. There's a newly opened Bugzilla [18]bug #1982278 tracking this issue. If you suspect that it might be affecting you, then you can use Firefox's built-in process monitor to see what it's up to: type about:processes in the address bar.
The GUI option just hides the mindless-chat-bot integration. You can also disable it more thoroughly via the about:config settings screen. The magic key that you need is called browser.ml.chat.enabled . This was found months ago – the earliest post we can find on Bluesky was from [19]back in February . Type about:config into the address box, then copy-and-paste the name of the key into the search box.
[20]Russia's RomCom among those exploiting a WinRAR 0-day in highly-targeted attacks
[21]IBM Cloud hit by Severity One incident with the same symptoms as other recent SNAFUs
[22]Infosec hounds spot prompt injection vuln in Google Gemini apps
[23]Perplexity AI accused of scraping content against websites' will with unlisted IP ranges
As a final step, if you want to feel a chill from a concern deeper than a mere ely… delete the final word in the key, leaving just browser.ml.chat , and watch well over a dozen more keys concerning hidden LLM-bot integration appear. Delete the last word again , leaving just browser.ml , and on our 27-inch monitor, the full-height Firefox window sprouts a scrollbar to show all the options. We have set everything to "false," and so far, nothing we use seems broken.
A Firefox spokesperson admitted: "We're working to improve client-side matching in the address bar, which makes it possible for users to recall previously visited websites without remembering exact keywords in the URL or page title.
"We unintentionally shipped a performance bug during the phased rollout of this feature, which processes information privately on-device. After receiving reports of issues that hadn't come up in our testing, we reversed the rollout and the performance issues should be resolved. We are working on a fix."
[24]
When we asked about inference, the spokesperson said: "Inference is an isolated process in Firefox responsible for private on-device AI inference, like language translation for websites.
"The rollout has been reversed, so performance issues should be resolved without users doing anything. "If a user would like to disable all local inference features, they can toggle the browser.ml.enable preference in about:config about:config ."
And of course Mozilla is far from the only offender. There really is no escape from the tentacles of [25]tech-clueless management's efforts to forcibly insert "AI" everywhere it can possibly go. ®
Get our [26]Tech Resources
[1] https://www.reddit.com/r/firefox/comments/1mkgdcm/inference_causing_cpu_and_power_spikes/
[2] https://www.theregister.com/2025/03/04/firefox_136/
[3] https://www.panmacmillan.com/authors/douglas-adams/the-meaning-of-liff/9781035051458
[4] http://meaningofliff.free.fr/definition.php3?word=Ely&lang=
[5] https://support.mozilla.org/en-US/kb/ai-chatbot#:~:text=How%20to%20remove%20the%20AI%20chatbot%20shortcut%20from%20your%20Firefox%20sidebar&text=%2C%20select%20Browser%20Layout%20and%20choose%20Show%20sidebar.&text=the%20settings%20button-,.,in%20the%20Firefox%20tools%20section
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[7] https://github.com/zen-browser/desktop/discussions/6236
[8] https://support.mozilla.org/bm/questions/1497223
[9] https://connect.mozilla.org/t5/discussions/please-keep-ai-out-of-firefox/m-p/70785
[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[12] https://www.theregister.com/2025/04/30/firefox_thunderbird_138/
[13] https://support.mozilla.org/en-US/kb/tab-groups
[14] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[15] https://www.theregister.com/2025/07/23/firefox_141_relieves_linux_pain/
[16] https://support.mozilla.org/en-US/kb/how-use-ai-enhanced-tab-groups
[17] https://allpoetry.com/All-Watched-Over-By-Machines-Of-Loving-Grace
[18] https://bugzilla.mozilla.org/show_bug.cgi?id=1982278
[19] https://bsky.app/profile/mastodon.peterjanes.ca/post/3lhwbx3n63bh2
[20] https://www.theregister.com/2025/08/11/russias_romcom_among_those_exploiting/
[21] https://www.theregister.com/2025/08/12/ibm_cloud_severity_one_outage/
[22] https://www.theregister.com/2025/08/08/infosec_hounds_spot_prompt_injection/
[23] https://www.theregister.com/2025/08/04/perplexity_ai_crawlers_accused_data_raids/
[24] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[25] https://www.theregister.com/2025/07/08/firefox_isnt_dead/
[26] https://whitepapers.theregister.com/
Mozilla, in its finite wisdom, embedded LLM bots into recent versions of Firefox for the vitally-important purpose of… naming tab groups . Now, some users are [1]noticing CPU and power usage spikes caused by a background process called Inference . All we have so far is a smoking gun, but it does look like Mozilla's product management has maintained its laser-like aim at its own feet.
This looks like an unfortunate sequel to a series of recent stories from The Register . First, in March, we reported that [2]Firefox had built-in vertical tabs . In the second screenshot in that story, you can see something that reminded us of the wisdom of [3]Douglas Adams and John Lloyd : a quietly terrifying [4]ely of looming "AI" integration into Firefox.
ELY (n.) – The first, tiniest inkling that something, somewhere has gone terribly wrong.
The worrying sign to which we are referring here is the first button in the group at the bottom of the tab sidebar: AI chatbot . As soon as we found it, this vulture immediately [5]disabled it . The Irish Sea wing of Vulture Towers is a proudly and resolutely LLM-bot free zone.
Due credit to Mozilla here: this chatbot integration is easy to turn off. You can do it via the GUI – it's on the Settings screen behind the last button, ⚙️ Customize Sidebar . The first option in the section headed Firefox tools is AI chatbot . Untick for instant relief.
[6]
It's not just us. Quite a few users are asking for this, with pleas such as [7]Remove Firefox "AI Chatbot" Feature or [8]how to remove AI from my Firefox? or [9]Please keep AI out of Firefox .
[10]
[11]
Even so, it's metastasizing.
In April, we reported on the new [12]Tab Groups feature in Firefox 138 – although at the time we noted that we didn't seem to have it in our copy yet, presumably due to Mozilla's "phased rollouts" which means that new features aren't immediately enabled for all users. Mozilla has [13]instructions on how to use them , either by drag-and-drop or context menus.
[14]
Then in July we [15]reported on the next installment : Firefox 141 now has an odious new feature Mozilla dubs [16]AI-enhanced tab groups , to which the company adds a box called Things to keep in mind –
Firefox uses a local AI model to read your open tabs' titles and descriptions to suggest more tabs and group names. Everything happens on your device.
What an inspirational use of technology, to relieve the insufferable burden of thinking of a single-word name for an ephemeral group of web pages! However did we live without the guiding hands of these [17]machines of loving grace ?
To be fair – we are obliged to – it's not yet certain that this is the issue. There's a newly opened Bugzilla [18]bug #1982278 tracking this issue. If you suspect that it might be affecting you, then you can use Firefox's built-in process monitor to see what it's up to: type about:processes in the address bar.
The GUI option just hides the mindless-chat-bot integration. You can also disable it more thoroughly via the about:config settings screen. The magic key that you need is called browser.ml.chat.enabled . This was found months ago – the earliest post we can find on Bluesky was from [19]back in February . Type about:config into the address box, then copy-and-paste the name of the key into the search box.
[20]Russia's RomCom among those exploiting a WinRAR 0-day in highly-targeted attacks
[21]IBM Cloud hit by Severity One incident with the same symptoms as other recent SNAFUs
[22]Infosec hounds spot prompt injection vuln in Google Gemini apps
[23]Perplexity AI accused of scraping content against websites' will with unlisted IP ranges
As a final step, if you want to feel a chill from a concern deeper than a mere ely… delete the final word in the key, leaving just browser.ml.chat , and watch well over a dozen more keys concerning hidden LLM-bot integration appear. Delete the last word again , leaving just browser.ml , and on our 27-inch monitor, the full-height Firefox window sprouts a scrollbar to show all the options. We have set everything to "false," and so far, nothing we use seems broken.
A Firefox spokesperson admitted: "We're working to improve client-side matching in the address bar, which makes it possible for users to recall previously visited websites without remembering exact keywords in the URL or page title.
"We unintentionally shipped a performance bug during the phased rollout of this feature, which processes information privately on-device. After receiving reports of issues that hadn't come up in our testing, we reversed the rollout and the performance issues should be resolved. We are working on a fix."
[24]
When we asked about inference, the spokesperson said: "Inference is an isolated process in Firefox responsible for private on-device AI inference, like language translation for websites.
"The rollout has been reversed, so performance issues should be resolved without users doing anything. "If a user would like to disable all local inference features, they can toggle the browser.ml.enable preference in about:config about:config ."
And of course Mozilla is far from the only offender. There really is no escape from the tentacles of [25]tech-clueless management's efforts to forcibly insert "AI" everywhere it can possibly go. ®
Get our [26]Tech Resources
[1] https://www.reddit.com/r/firefox/comments/1mkgdcm/inference_causing_cpu_and_power_spikes/
[2] https://www.theregister.com/2025/03/04/firefox_136/
[3] https://www.panmacmillan.com/authors/douglas-adams/the-meaning-of-liff/9781035051458
[4] http://meaningofliff.free.fr/definition.php3?word=Ely&lang=
[5] https://support.mozilla.org/en-US/kb/ai-chatbot#:~:text=How%20to%20remove%20the%20AI%20chatbot%20shortcut%20from%20your%20Firefox%20sidebar&text=%2C%20select%20Browser%20Layout%20and%20choose%20Show%20sidebar.&text=the%20settings%20button-,.,in%20the%20Firefox%20tools%20section
[6] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[7] https://github.com/zen-browser/desktop/discussions/6236
[8] https://support.mozilla.org/bm/questions/1497223
[9] https://connect.mozilla.org/t5/discussions/please-keep-ai-out-of-firefox/m-p/70785
[10] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[12] https://www.theregister.com/2025/04/30/firefox_thunderbird_138/
[13] https://support.mozilla.org/en-US/kb/tab-groups
[14] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[15] https://www.theregister.com/2025/07/23/firefox_141_relieves_linux_pain/
[16] https://support.mozilla.org/en-US/kb/how-use-ai-enhanced-tab-groups
[17] https://allpoetry.com/All-Watched-Over-By-Machines-Of-Loving-Grace
[18] https://bugzilla.mozilla.org/show_bug.cgi?id=1982278
[19] https://bsky.app/profile/mastodon.peterjanes.ca/post/3lhwbx3n63bh2
[20] https://www.theregister.com/2025/08/11/russias_romcom_among_those_exploiting/
[21] https://www.theregister.com/2025/08/12/ibm_cloud_severity_one_outage/
[22] https://www.theregister.com/2025/08/08/infosec_hounds_spot_prompt_injection/
[23] https://www.theregister.com/2025/08/04/perplexity_ai_crawlers_accused_data_raids/
[24] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/front&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aJxiNjAeBIxAZGLNCQRvwgAAAEw&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[25] https://www.theregister.com/2025/07/08/firefox_isnt_dead/
[26] https://whitepapers.theregister.com/
wolfetone
What has Clippy done to be compared to AI?
Please Mozilla
Dan 55
If you must insist on this crap to not feel left out, include an AI settings page with a toggle switch for each AI feature and another switch for 'shut it all off' for those who don't want anything. Don't hide it in about:config and make people search the internet for settings.
lglethal
Firefox management really dont get there Userbase, do they?
Generally more tech saavy folk, who hate the dominance of the big boys, and the constant push from tech bros to chuck the latest fad in everything. Soooo what do they do, start copying said tech bros, and trying to imitate the big boys.
Someone needs to educate them with the Clue Bat...
wolfetone
Well that's going to be me removing and preventing Firefox from being installed on the work machines this week.
Thanks Mozilla.
Worrying.
Mage
More proof that Mozilla has lost the plot. I thought just GUIs (they destroyed Thunderbird GUI being able to be like desktop after 91.x).
Go about:config
type chat into search.
Much stupidity.
In Settings, see Browser Layout. They have also disabled copy on selected text in Settings and About screen
Firefox 141.0.3 for Linux Mint
...and so far, nothing we use seems broken.
Neil Barnes
Which returns to my comment about user interfaces a few days ago: you can see all the switches but there is little clue as to what many of them do.
But thanks, I've also made them all 'false'.
(Probably unconnected, but I note that using Zoom in the browser drives four cores close to 100%, combined with several seconds lag between incoming audio and video. It _used_ to work...)
and another thing
The Central Scrutinizer
"Due credit to Mozilla here: this chatbot integration is easy to turn off"
Hardly the point though, is it Liam? Absolutely nobody asked for it in the first place.
I know I know, you were being professional with that point, but still...
Re: management's efforts to forcibly insert "AI" everywhere
Flocke Kroes
I thought they wouldn't replace management with AI but perhaps this is evidence that I was wrong.
Done
AlanSh
I've set everything 'false' that I can see - rebooted the whole PC and FF does seem a bit more 'snappy'.
Alan
Having read this and other recent articles about so called AI basically causing all sorts of nasty/weird shit to happen, I really am starting to despair at where the computing world is headed. Shoehorning new, unproven technology into everything "just because we can" never ends well.
I'm hardly a luddite, but for fuck's sake.... knock it off.
AI, the new Clippy.