@Angela7 Try configuring Deco Main Network to run on 5GHz band only: Repeat speed tests after that.

@Machineage I think going with three Deco nodes the way you plan should provide good WiFi coverage for Master Bedroom. In regard to future proofing. Both M9 Plus and X50/X55 can do just fine with...

@tinyDANster Do a simple test that will help with troubleshooting: Bring Main Deco to where AT&T modem or switch are, and connect AT&T modem through Main Deco to the switch AT&T modem <--Ethernet-->...

@Machineage With that detailed description and a floor plan it would not be hard to provide proper recommendations. ------------- Type of Deco units (Deco model). For Internet speed of 100Mbps there...

@phad Yes, too much of a mess. I don't think I can offer any more help. I think the best would be for you to discuss these findings with your ISP Tech support and ask for explanation. The Internet...

@phad Can you give me a hint which one is right and which one is not? Also, one more test: connect same laptop with Ethernet cable to Main Deco, so that it connects to Internet through Main Deco, and...