@Oldmanlight 

Disable any QoS or priority features when doing the test. Power down the satellite units and focus on the main unit. I would also temporarily change the network name to something else so one device is connected not others. 

If testing from a satellite unit, make sure the testing device is connected to the closer node. The Deco will try and recommend the best node to connect to, but you may still be connected to the main Deco while close to another. You can also disable and enable the wireless connection which should solve that. 

If performance is not good with the main Deco node, swap it with one of the satellite units. 

If it is possible to connect the Deco nodes via Ethernet cable, that will provide the best possible speed.

If you still feel the system is not working as you would expect, please reach out to our support to troubleshoot.

@Tony sorry but your suggestion doesn't even sound like you're understanding the setup. this is a wired connection to a switch port on the back of a 𝗪𝗶𝗳𝗶 router. Not a mesh node, not a mesh network.  Without qos, the bloat is even worse on outbound traffic.