@zcx This TP-Link FAQ article may help, too: How many Deco units can I add to my Deco mesh network? If you run Deco mesh in AP mode, my recommendation would be not to connect all Satellite Deco...

@HSSG Do you have WiFi still enabled on modem? What you describe may be happening if some of devices connect to modem WiFi and some - to Deco WiFi.

@Oliblo 15m is close to maximum recommended distance between Deco units, and that when there is open space between them. If there are walls the recommended maximum distance will be less. You can try...

@Trs_ This is probably just different product description at different web sites. I can go very technical, if you want to waste my time and yours, but I would rather start simple: for the purpose of...

@Trs_ Trs_ wrote Do you know if I will be able to find out if the ports are giga or dual band? If you are talking about Ethernet ports, what is "dual band Ethernet port?" Can you give me a definition?

@MD80 Hint: if you configure Guest network WiFi run on 2.4GHz only, that could offer at least some bandwidth throttling.