@ScottieNim 

I run Deco mesh consisting of two M9 and one M5. Deco M9 is tri-band, with dedicated WiFi backhaul. Deco M5 is not. They will work together just fine, but with single M9 in the mesh dedicated backhaul won't be utilized.

There is no benefit in adding M9 as Satellite Deco to M5 setup. From the other hand, M9 delivers better performance, and under some conditions it could make sense to have it as Main Deco.

To assess if M9 will benefit your Deco mesh when running as Main Deco, please answer these questions:

1. Do you run Deco in Access Point or in Router mode?

2. Do you have Satellite M5 connected with Ethernet cable, or do they all connect wirelessly?

3. When you touch your Main Deco, is it hot on touch? Not just warm, it'll be always warmer than room temperature, but does it feel hot?

4. What is Internet speed provided by your ISP?

@Alexandre. 

Thanks for that..

In response to your questions 

1. Deco runs in Router Mode

2. All M5's connect wirelessly

3. it's always warm but never what i would call hot

4. Currently getting around 380Mbps DL / 35Mbps UL

This is where i thought the benefit may be using the M9 as the main node.. just wasn't sure what the benefit (if any) was

Thanks

@ScottieNim 

It does not look like you'll get much by replacing Main Node M5 with M9, in your setup. It appears your Main Node runs just fine, does not overheat. Internet speed is below of what M5 can handle.

Also, it makes sense to run all mesh on same hardware, because every time there is firmware update you'll get it to all your nodes and your mesh will use them. For example, for a while I had M5 on firmware 1.5.1 while M9 was behind with 1.4.3. As a result, all new features introduced in 1.5.1 for M5 weren't available in my Deco mesh network.

Yet, if you want to hear arguments for making M9 Main Node in your network, here they are. They will be mostly based on the fact that M9 is more powerful Deco unit than M5. Just look at M5 and M9 power supplies plugged side by side, M9's is on top.

That power must go somewhere, right?

In general, one should expect M9 better handle router functions of Deco mesh, including everything related to traffic management: parental controls, antivirus, blacklisting. 

When it comes to speed of WiFi connection between Main Deco and mobile device, the best I've got from M5 was 460Mbps. Same smartphone, but connected to M9: 630Mbps best result.

If you plan to expand your Deco mesh even further in the future, and already have M9 as a Main Node, you could buy another M9 and make it Satellite Node where it counts: replace most utilized M5 with it, and the one that has strong WiFi connection (Signal Strength) to Main Node.

In my test, the best I've got from wirelessly connected Satellite M5 was 225Mbps, while same smartphone connected to Satellite M9 (with Main M9) got 400Mbps. Dedicated backhaul matters.

Major caveat: all speedtest results I refer to are best of the best, after dozens and dozens tries. Routinely, I am getting less than these peaks, but these peak numbers help to assess top performance of both M5 and M9, and compare them.