Too many tris verts limits my framerate...am I CPU or GPU bound?

I need to determine whether I am CPU or GPU bound to further optimize my game. Right now I know the number of Tris 'Verts is the limiting factor.
Does this automatically mean I am CPU bound?

I've tried unsuccessfully to reduce the screen size of my output to my targeted device (iPad Pro) as a test to determine if I am CPU or GPU bound.