Soldato
My specs are very similar to yours and I have to say that IS disappointing.
But that depends on what levels you're running the game at.
Surely that can be scaled back.
I've tried low, medium, high and even Ultra and I have the same issue.
1080p
Infact on low settings my 1070 shows 40-50% usage but my CPU is locked at 100% still.
I've just received a 5820k today so will see what difference that makes.