If NV Inspector shows the VPU (video processing unit) not showing activity whilst playing VP9, then it must be turned off in the drivers, and NVidia will have to enable it in a future driver update..I'm using nvidias newest hot fix drivers aka 368.51
I downloaded the program you recommended and my gpu usage isn't going above 10% and the VPU is staying at 0. Any suggests or ideas as to why this would happen? The videos play just fine and checking my cpu it looks like this time around its sitting around 40% instead of the higher 70% ish that I was seeing prior, but im assuming it should be lower with the gtx 1080.
Let me know if there is another way I can test to see if the VPU (no idea what that stands for or is) is actually working on this card.
Why it wasn't ready for the Pascal launch is anyone's guess.. Still, I would report it as a bug over at Geforce forums if I were you, just to make sure they are aware of it. Very likely they already are though.