"The software doesn't perform well with your use case, huh? Have you tried getting a different use case?" :)
CPU doesn't execute <program> fast enough. Have you tried a different <program>?
It certainly wasn't add-ons. Firefox has a long history of performance issues.
EDIT: I see the firefox brigade is out in full force.
Re:Firefox 82
by JoshTriplett on Tuesday October 20, 2020 @01:49PM
(#24840321)
The comment I was responding to specifically said "found it to be too slow once all add-ons were included", so I don't think it's at all unreasonable to talk about the add-ons. That doesn't mean I'm dismissing the possibility that Firefox itself had a performance issue as well.
That sounds like it's likely to be a performance issue within one or more of the add-ons. Which add-ons are you using? There may be better alternatives that don't cause performance issues.
If Firefox is fast enough for you now with your add-ons, it would be even faster with a more optimal set of add-ons.