@rb75
Hey
Hopefully we will be able to help you
Question 1: Speed
If I stand right in front of the Main X60, hardwired into the modem which is pumping out 900 Mbps Can I ask how you tested this?
I was surprised I only get 80-120 Mbps WiFi speed on my iPhone 12 Pro. Shouldn't I be seeing faster speeds? Are you connected to the 5Ghz or the 2.4Ghz and again what are you using to test this? That speed would indicate a 2.4Ghz connection to the x60. If you plug a laptop / desktop into the 2nd port on the main hub (one connected to router) do you get the full 900 via cable?
I experienced similar speeds on the 3rd level, near the other Deco X60 hardwired. On the 2nd level I was getting 70-90 Mbps. I have QoS set to 'Standard' and removed priority devices. The nodes will use the WiFi as a backhaul so that could be a restriction. We need more info before guessing on this one. Start with the main hub first.
Question 2:
Does passing through the X60 dampen speed? Yes.. and no.. depends.. If connected via cable all the way then likely NO it wont slow you. However if you are cabled into the 3rd node (3rd level) then dispite this being cabled to level 2, the link to the main router is a WiFi backhaul (wifi connection to 1). WiFi simply isnt a fast as a cable and the chance of getting 900mbps is, well honestly slim at best. WiFi speeds top out around 600mbps from my experience.
I had my Ethernet pass through an X60 on the way to my son's computer. He was getting 300 Mbps. When I went direct (vs through the X60) his speeds went back up to 900 Mbps. Is this normal? To be clear when you mean "through the x60" you mean that its cabled into it? therefore again the WiFi backhaul is likely the issue getting "wirelessly" to the main node. Also when you say direct you mean straight to router?
If i was you, i would start testing this in the same room.. take 1 of the nodes offline.
Try a laptop into the same x60 as the router.. then try the same laptop into the 2nd x60 (router plugged into other). This will indicate if the WiFi backhaul is the slow bit
Then we know more. Mesh setups are great.. however they are WiFi Mesh and therefore you are never going to get cable speeds. Anything around 500+ is good for WiFi, if you want faster you need to cable these.
Mesh ultimately is designed for coverage over speed, you get wide coverage at moderate rates but due to the mass amount of wifi its slower.
Try these tests and update so we can take a look