There is a giant confusing tech stack here, but opening up this simple plain text page resulted in like 100% CPU usage from from gnome-shell when visiting from firefox on a pretty non-customized Ubuntu 24 install.
In the firefox task manager nothing really looked odd, but opening that tab and displaying it is insanely CPU intensive.
Pausing the autoplaying video makes it seem like a sane web page in terms of CPU usage. I'm surprised how much CPU playing that video consumed.
Very odd. This must be some kind of Ubuntu issue. Out of curiosity I tried it in Chrome, Firefox and Safari on MacOS 15.5 and saw very little CPU usage and no difference with/without the video playing. I don't have a Ubuntu Desktop handy to confirm. Looking at the video it's nothing special. Just a fairly small mp4 using a native html5 video element to play it. Really no reason this should be causing issues.
Yeah, totally agreed. It was quite surprising to me. Who knows it may even be related to the random GPU I happen to have or ....