Pretty much every time I've used nvtop it has been while doing CUDA stuff, mostly to see if it was going to blow out the memory but also to spot check that the model is actually using the GPU. I've had times where it said it was using the GPU, but it only did so for the first part of the work and then dropped down to the CPU for the rest.

Yes, indeed. But 90% of my very own GPU usage is for WebRTC based applications and web-based videos.

Which leads to what I said: no hw-assisted encoding/decoding actually available.

I use intel_gpu_top (from intel-gpu-tools) to monitor my GPU usage: only VLC shows usage.

Anyone has success with browsers?

Yes, you can see video decoding, but it's indeed only one detail of the data presented, as it's only a part of the HW.

Not at my computer now, can't tell what metric to watch.

Which software would use video decoding?

Pretty much everything except the browsers.

I use several video players, including mpv, vlc and ffmpeg, and they have always used without problems the hardware video decoding and encoding on all kinds of GPUs.

Only with Firefox and Chrome/Chromium in most versions the hardware acceleration is broken, even if there have been some versions where it worked fine (on NVIDIA), but at the next browser upgrade it was broken again.

This does not bother me much, because I do not like to watch video files in a browser anyway. I always download them first and I play them locally.

Ah, OK. Then we are on the same page.

Sadly enough, I need the browsers to use hw-assisted en/decoding for my video communication... Which seems to be little more than a dream, ATM.

ah yes, you can configure nvtop to display encode and decode loads. Interesting to watch how playback speed in VLC is directly reflected in the metric.