Firefox users report high CPU and memory usage in the latest release, caused by browser’s on-device AI inferencing for its ‘smart tab grouping’ feature.
https://www.omgubuntu.co.uk/2025/08/firefox-high-cpu-usage-inference-disable
#mozilla #firefox #opensource
Here’s the bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1982278#c4
It does not appear to be caused by smart tab grouping (which you also have to actively enable yourself).
it was enabled for me and I just took it off. I ever enabled it so it must be default to have it on.
If by “enabled” you mean you saw a button “Suggest more of my tabs”, then I believe that is present by default, but I believe it only downloads the model when you actually press that button for the first time. At least it did for me.
It’s possible that I’m misunderstanding what it does otherwise though. Still, does not appear to have been the cause of this particular issue.
nope. literally says “Use AI to suggest tabs and a name for tab groups” and the slider was activated and I flipped it to off. Never saw a download but when it updates firefox either has to be closed or it restarts.
Weird, I don’t even see a slider! Perhaps we’re in different testing groups or something.
im on linux and using what I think is bog standard firefox with a few addons.
Same! But I think people are just randomly sorted in buckets to see how some experiments land.
I am on an lts kernel (ubuntu) to. not sure if that would make a difference.
I doubt it, but yeah - Fedora Silverblue here, who knows.