After recently having upgraded my internet to gigabit, I noticed that the speeds I was getting on devices connected via Ethernet were somewhat lacking. After a lot of back and forth, testing and controlling cables and trying different physical configurations I've come to the conclusion, that when my Deco M5 is connected to my network, my Ethernet speeds go down from about 950/950 Mbps to around 90/90 Mbps.
My standard setup is like this: My modem is connected to a router, which is then connected my main M5. The main M5 is connected to a switch which also holds Cat 6 cables to the different rooms throughout the house. One of those cables goes to my living room where I have yet another switch connecting my TV, PS4, second M5 unit and so forth to the network. The third M5 unit is connected via WiFi in the opposite end of the house.
With all the M5s unplugged and turned off everything is fine and my speeds are perfect, but as soon as they're on and connected and my modem and router has been restarted it's back to below 100.
I came across something about backhaul and looping, but I'm not sure i understood exactly what is was about.
Any help is greatly appreciated.