Some testing later, and I'm now certain that it's specifically Youtube (and *only* Youtube) that slows down Firefox to a crawl.
@riley Whatever it is, it's clearly not working because I don't see ads on Youtube to this day
@joepie91 that sounds familiar. Ublock works overtime on that site, so I guess it's slinging loads of crap at you while you try to watch something.
@joepie91 oh yes, youtube tabs have gotten way more intensive recently in firefox. i think it's to encourage people to switch to chrome.
@bananas Right, I had noticed that - but the thing I was unsure about was whether it was specifically Youtube, or rather caused by eg. a specific browser feature that Youtube happens to use.
And well, the answer seems to be "specifically Youtube", which suggests intentionality.
@bananas Also, it has mostly just encouraged me to start using my local music library again 🤷
@joepie91 Yup, I've read some posts on here lately from people who experienced the exact same thing. Seems like Google really doesn't want you to use Firefox for YouTube (most likely because of the ability to still use adblockers). Which just means I'm using YouTube less and less 🤷🏻♀️
@joepie91 yeah I have been pretty certain of this for a while. Performance has just been consistently worsening for years and to the extent that things even have workarounds or solutions they involve features that have no reason to be performance intensive at all, like theater mode dimming the page. I haven't had access to my PC for a month now, but then it had gotten to the point where it would regularly take 6-7 seconds to register when I pressed play/pause or the skip keys. I haven't heard anyone else say that, so maybe it was an extension interaction, but I don't know. And the idle CPU use was also very high.
@someonetellmetosleep The "takes several seconds to register play/pause" is something I consistently experience when I've had a bunch of Youtube tabs open for a while, even if none of them have actually played a video yet.
@joepie91 My impression is, it's doing something weird for adblock suppression.