macuser:
I have a Netgear R7000 and always hit 200Mbps even over wifi (my fibre connection speed) so I think you've still got something configured wrong.
All ports on the R7000 + R8000 are gigabit.
I think everything points to that being the case, but you cant configure the RJ45 ports so I really have no idea. Im gonna take it back to PB Tech and see what their tests get out of it.
