@M4DECO I am having the same issue.

Wireless speed is capped at 94mpbs for me unless the slave unit has gigbait ethernet cable connected to the slave M4.

So this is my set up

FTTP (@940mbs) 

Zytech router (940mpbs when connected to wifi) - CAT 7 cable to

M4R - (940mpbs when connected via ethernet cable - 505mpbs when using wifi) connected ( via CAT7 cable to )

M4R (Slave 1) - (wifi varies massively from 200mbps to 500mbps) connected via wifi mesh to

M4R (Slave 2) - Maximum 94mpbs.

I have tried moving the Slave 2 unit to different locations including line of site but it only seems to working at very very slow speed.  20-94mbps from this unit.

I know the unit is fine as I created a separate network with it to test it and the speeds of wifi connection exceed 200mbps.

I'm dissappointed at the wifi speed that these units in general produce but Slave 2 speed is just no good.

Can anyone assist with any ideas (really don't want to run more CAT7 around the house)

 

  @M4DECO 

Here is what you can do to find the maximum WiFi performance Deco mesh can deliver at your place. I am assuming your Main Deco is still connected to zhone router, right? If it is, please do the following two changes in Deco app:

1. Change Deco Operating Mode to Access Point. This will maximize performance of Deco hardware. See How to set up Deco to work in Access Point mode

2. Under WiFi Settings, configure Main Network to run on 5GHz only:

After that, power off all your Satellite Deco and keep only Main Deco running. If speed test result is not satisfactory for you in this setup, just pack M4 set and return it back to seller for refund. 

If with that configuration you'll get WiFi speeds on Main Deco that are acceptable to you, so that you'll consider keeping Deco M4 set, let me know and I'll explain what to expect from Satellite M4 and how to place them optimally. Also, check my reply to @Troy73 on the topic of satellite Deco, in this thread.

  @Troy73 

With Satellite nodes connected wirelessly to Deco mesh, you will be losing 1/2 speed, comparing with node Satellite is connected to. It is the limitation of technology. Google "Why do Wi-Fi range extenders cut bandwidth by half" for more detailed explanation. Note that Satellite Deco is same as range extender when it comes to WiFi speeds it can deliver.

You didn't tell where your Satellite 2 is connected, to Satellite 1 or to Main Deco. Assuming Satellite 2 is connected to Satellite 1, this is what you should expect to have when Deco nodes are connected to each other wirelessly:

M4R (Main) - up to 600-650Mbps under ideal conditions (you have 505mpbs when using wifi, it is good speed)

M4R (Slave 1) -  1/2 speed of M4R (Main) (expect 200-300Mbps, more than that is an exceptional result)

M4R (Slave 2) - 1/2 speed of M4R (Slave 1) (expect 100-150Mbps, more than that is an exceptional result)

Which means, your speeds are what your should be getting from that type of hardware, and this is applicable to any WiFi5 mesh, not just from Deco.

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Satellite Deco that is connected by Ethernet cable to Main Deco will deliver same WiFi speeds as Main Deco.

If you can connect M4R (Slave 2) to M4R (Slave 1) with Ethernet cable, M4R (Slave 2) will deliver M4R (Slave 1) speeds (up to 200-300Mbps).

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With Satellites connected wirelessly, you might get better results with tri-band WiFi mesh, but it will cost you more. If you want close to WiFi gigabit speeds, you will need WiFi6 capable mesh, it'll cost you even more. From TP-Link line of Deco models the following are tri-band WiFi6: X68 and X90. 

  @Alexandre. 

The Slave 1 unit is connected to the master via CAT7 

As such I would expect the master to be acting as a passthrough (which it does it you connect via ethernet)  As such I would expect the wifi speed to be similar to the master.

As for the 3rd unit (slave 2) - that is connected via WIFI.  However I only get between 20-94mbps.   It is within 4 meters and has line of sight to slave 2.

However looking at it today it is getting it's signal from the master via wifi.  The master is 10 meters away and a floor down.  It is possible that is the reason why the speeds are so slow.  It isn't connected to it's nearest unit.

Without a way to make it connect the third unit (slave 2) to the second (slave 1) it to keep rebooting it / moving it closer to slave 2 / resetting them all.

Until it does connect to the slave 2 unit I will not be able to get a true reflection of the situation.

It would be useful if TP-Link software had a way to move where slave units got their primary signal from.

  @Troy73 

When Satellite is connected to Main with Ethernet cable, they both should deliver same WiFi speeds. Reasons Satellite is not could be issue with Ethernet cable, some sort of WiFi interference around Satellite, and if device you use to test speeds jumping between Main and Satellites without you noticing it (which impacts speed test results).

Also, review this document: General questions about Ethernet Backhaul feature on your Deco

>[Slave 2] it is getting it's signal from the master via wifi.  The master is 10 meters away and a floor down.  It is possible that is the reason why the speeds are so slow.

It is possible and easy to confirm. When you check Satellite 2 Signal Source, see what it shows for signal strength. Should be two or three blue bars for good link. Example:

This Satellite has two blue bars in link strength. Anything less than that means Satellite is too far from Deco it is connected to and won't deliver decent WiFi speeds.

>It would be useful if TP-Link software had a way to move where slave units got their primary signal from.

Yes, it would. This feature is already available in Deco M5 official firmware, and beta firmware for M9 Plus is shared with forum users. TP-Link might have beta firmware for M4, but they haven't shared it with wide audience yet. You can send PM directly to @David-TP , this is TP-Link Support account that shares firmware beta for different Deco models, and ask for it. You only need to install beta firmware on your Slave 2.

  @Alexandre. 

Thank you for ur quick reply

I will try the ap mode and will let you know about the speed performance of my main deco 

And get back to you to help about placing the slaves optimally

Many Thanks