nvidia – Issue when using GPU using Bumblebee (Debian)

I just upgraded to debian bullseye and I had to set up again my Geforce MX150.
I followed the instructions in here yet I am finding some weird behavior:

  1. If I run ‘optirun glxgears -info’ I get 70 frames/sec and glxgears appears in nvidia-smi (meaning, it is running via GPU) yet my CPU is running glxgears at 110%.

  2. When I run ‘primusrun glxgears -info’ it runs at 60 frames/sec and glxgears appears in nvidia-smi and the CPU usage is 90%

  3. If I run ‘glxgears’ runs at 60 frames/sec, it doesn’t show up in nvidia-smi and the CPU usage is 7%.

So I am confused, in the test 1 and 2 the CPU usage should be a way lower since it says (at least nvidia-smi) that it is running on the GPU, and in test 3 the CPU usage should be higher since it is running on CPU. Plus, the frame rate seems to be the same in the 3 different tests.

Is my GPU actually running the processes? Any suggestion?

Thank you very much