[StilesCrisis]

It sounds like Firefox needs to implement hardware assisted AV1? I don't see how you can plausibly blame anyone but Mozilla for this.

[AVocaloidFaN]

Firefox has had AV1 HW decode for years.

I wonder if he's using a Radeon gpu, those have had issues like video playback making the entire ui framerate drop. But it happens in steam/electron too, not only firefox. The shader cores aren't used much either, it's just a bug.