Found the solution after trying many combinations. The deco has two Ethernet ports. My initial connection  was from router to deco was in port 1. Whe I changed to port 2 from routerI started getting same speed as router.
 

Those who are facing low speed in deco check whether you connected in port 1 or 2 from router using cat6 cable. Change the connection to port 2

 

Amit9215 wrote

Found the solution after trying many combinations. The deco has two Ethernet ports. My initial connection  was from router to deco was in port 1. Whe I changed to port 2 from routerI started getting same speed as router.
 

Those who are facing low speed in deco check whether you connected in port 1 or 2 from router using cat6 cable. Change the connection to port 2

@Amit9215 

 

When I run speedtest (laptop wired to slave M4*, slave is WIFI to MAIN M4)  I get faster times with exactly the opposite:

167/24 vs 254/34, when I use the bottom then the top port (2 vs 1).

 

300mbs service.

 

So if one way doesn't work fo you, try the other.

 

*laptop is wired to the lower port on the slave M4

So.. I have done some troubleshooting and this Deco M4... I must say, really disappionted. 
I have fiber from my ISP 500/500 MB line. 

Gone through the suggestions in this thread and others, but I can not get full speed on the Wifi. 
When i connect to the Master/main Deco wired with PC i get allmost 500/500MB so that is great..guess the last test was 480ish MB down and 490ish MB up.. 

BUT
When i disconnect and use WIFI i loose 200MB+++ both down and up. Just pulling the cable out an use Wifi sitting beside it, running Ookla speed test again.

Connecting to the other slaves (3-pack) with cable i get different results eatch time - in the 200-300MB range.. 
Pull the cable out and use wifi I am only getting 150-180 MB download and 122ish upload. 
Slaves are placed in the basemant and 2nd floor, master in 1st floor. MASSIVE DROPP

Cant see the point in using this product or paying my ISP for the speed when this HW is NOT compatible to handle the speed.. 

If this has something to do with the 2.5Ghz, then a FW update is needed so that we can have dedicated SSIDs 2.5ghz and 5ghz 

Regret bying this product and will write a really bad review where I bought it... so hopefully people stay awat from the Deco M4...

 

IF there is a FW fix for this and its coming soon - please shout out! :/ 

 

BR

NotSo-MeshedUP

Do you have a modem/router? If so is the wifi turned off on it so it does not conflict with the Deco acting as the router?

@nesbocaj 

Hi

Yeah the Deco is connected to my IPS router and it is set in bridge mode.. 

But never checked if the wifi is off.. its worth a check I guess.. thank you.

@MeshedUP 

 

>If this has something to do with the 2.5Ghz, then a FW update is needed so that we can have dedicated SSIDs 2.5ghz and 5ghz 

 

That should already be possible according to TP-Link FAQ Changing the Wireless Settings on your Deco app. Check in your Deco app that you you can switch off the unwanted Wi-Fi band, such as 2.4GHz.

 

Alexandre. wrote

@MeshedUP 

 

>If this has something to do with the 2.5Ghz, then a FW update is needed so that we can have dedicated SSIDs 2.5ghz and 5ghz 

 

That should already be possible according to TP-Link FAQ Changing the Wireless Settings on your Deco app. Check in your Deco app that you you can switch off the unwanted Wi-Fi band, such as 2.4GHz.

@Alexandre. 

 

That is on Version 2.4.30.  for the M4 that I have

 

I wonder if you have a modem/router from your provider and you set the Deco to be 5ghz only and you set the modem/router to 2.5ghz, that you can increase coverage if say the modem/router is in an area of no wifi, ie a basement.

@nesbocaj 

 

You can, but in my house Deco provides strong 2.4GHz signal everywhere, so I separated 5GHz and 2.4GHz in Deco and that was enough. I pointed all devices which need 2.4GHz to Guest network:

 

 

 

Honestly very very bad and very limited interface. You can't do anything it with besides very basic stuff.

LAN ports on the device don't even have a LED!

But, that could be solved if in the informations from the DECO they add something as simple as the port Speed (mine keeps changing to 100 Mb/s and that creates the funnel in the WIFI).