I'm getting extremely slow network speeds after upgrading from a Deco M5 (3 pack) to the Deco X50 (3 pack)

 

I have managed switches 1GB ports (but not setup in managed mode) and a 330/50Mbps internet connection

 

On the Deco M5 I would get full 308Mbps down and 47Mbps up on all my devices whether wired or wireless.

 

Now I only seem to be able to get full speed on a few devices whether wired or wireless, while others I get full speed

 

My satilites are using ethernet backhaul and show this on the app,

 

so why are some devices only showing they can only get upto 45Mbps down and 48Mbps up?

 

ie Samsung S20 FE, Pixel 3XL, Samsung Tab S6, Apple TV 4K (Wired/Wireless), Shield TV (Wired/Wireless), will not acheive speeds over 50Mbps since switching to the X50.

 

I have also tested some wired devices and get mixed results, some will only now do less than 200Mbps while other do 308Mbs. Xbox Series X, gets full speed

 

QOS is not enabled (tested with enabled and disabled), I've tried with Beamforming and Fast Roaming enabled/disabled but still same issue

 

The CPU load is low on the deco's 

 

On checking my Huawei Mate 10 Pro this is showing connection signal strength excellent and link speed 702Mbps and can transfer at 300Mbps

 

My Samsung S20 FE is showing network speed of 864Mbps but can only do 50Mbps or below, yet on Deco 5 this is 300Mbps, this is the same for the Pixel 3XL.

 

So any help on this as picked these up in place of a faulty ZenWifi XT8 which when it wasn't crashing every few days was actually perfect performance.

 

Update 16/12: Upgraded the deco to the latest firmware manually and now get full speed across all units and devices attached