@topgazza1 

Hi, Thank you very much for the feedback.

Is 500m/s the 5GHz wireless speed from the iPhone when it is connected to the main Deco X20?

If yes, Deco X20 is WiFI 6( the maximum link speed over 5GHz is 1201m/s), while the iPhone is Wi-Fi 5, its maximum link speed(PHY rate) is 866m/s.

Wi-Fi specifications for Apple devices

500m/s via speedtest out of 866m/s PHY rate is quite great.

Have you ever tested the Ethernet cable speed from the main Deco X20?

I noticed you mentioned"However with 900 at the router and 890 according to the Deco speed test at the Deco it only outputs 500 Mbs near the main Deco"

I remember Deco X20_V3 doesn't support "Test internet speed" on the Deco APP.

Did you get 890m/s from the Ethernet connection of the main Deco X20? 

By the way, Did Deco work in wireless router mode or Access Point mode?

Wait for your reply and best regards.