Firefox isn't having a memory leak (RAM and CPU usage stays the same) nor is it maxing my GPU or anything like that. But if I watch enough of a 1080p60fps stream or enough 1080p60fps content in general (this stream is a notable offender: https://www.youtube.com/watch?v=W6OOnrx8g58), it'll start to slow down over time (generally a couple of hours) and [really chug and drop frames like its nobody's business: https://i.imgur.com/OmHqJ8a.png. This does not occur in Edge (the streams run silky smooth even after 2+ straight hours of watching), nor does it happen on other streaming sites like Twitch. It also doesn't happen in Firefox on my desktop. Regular 1080p60fps videos are MOSTLY unaffected. The buffer wheel animation in most videos is choppy and moving back/forth with the 5-sec rewind/ff feature results in a short, choppy buffer wheel on a lot of videos(https://imgur.com/tm1AtkB), even if the video itself is mostly unaffected. Some more "intense" videos will make the fan speed go up. HD videos are *slightly* less smooth when in this state. Unpausing a video often results in a short buffer wheel before the video resumes if left paused for at least a minute or so. I also get a tiny TINY bit of frameskip on the occasional Twitter video while in this "state". Its like the memory is "caching" something and killing the process clears that "cache", yet I have no idea what is actually doing this. Refreshing the page/closing and reopening the stream stream has no effect, its like an affliction and will still be choppy when you reload. Restarting the Firefox session or killing the process the stream or a video is running through fixes it for awhile (even if the stream stilll drops more frames overall than it would in Edge), but it feels like I have an "allowance" of 1080p60fps content before these streams start to chug. Nothing else in-browser is lagging at all.