I imagine, be he mentions video playback on youtube making things worse, and he does have a dedicated amd gpu.

But iirc for both Firefox and chromium on Linux desktop hw acceleration is tricky so maybe it's that.

Yes anything GPU related other than CUDA is a shit show on Linux desktop. Another issue is that YT loves to use AV1 if they know you're on desktop. Almost all desktop users have a CPU powerful enough to software decode it in realtime, but if you're on a prebuilt PC you'll definitely notice the fans kick in

	▲	theevilsharpie 3 days ago \| parent [-]
		I can't speak for Firefox, but Google Chrome (and presumably anything Chromium-based) has working hardware-accelerated video on AMD and Intel GPUs. It does admittedly take some effort to set up; I assume Google is hesitant to enable it by default because of issues with Nvidia GPUs. But when configured, it works and has for years.