Wired LAN Speeds very slow-RBR50

I have an RBR 50 in my office connected to a 608S 1Gb unmanaged switch in the room below that has two servers connected to it.  If I do a LAN speed check from one server to the other, via just the switch, I get over 550 Mbps.  When I do a LAN speed check from a PC wired directly to the RBR50 right next to it and then down to the 608S switch to one of the servers, I get barely 80 Mbps. Taking the switch out and going directly from the Orbi to one of the servers increased the speed very slightly, but nowhere near what it should be.  I have tried new cables with no change and the cables are all Cat 8, with the longest one being only 10 feet. 

Can anyone explain what the Orbi might be doing that would result in such a speed reduction.  Please note that this is all on wired LAN, not wifi and has nothing to do with internet speed.  

Thanks