@Arrowman 

Deco app speed test reports speed of wired connection between Main Deco and ISP modem/router. Do you have asymmetrical fiber? Because, with gigabit down and gigabit up, you should see same 900 Mbps down and up in Deco app. If you see 95Mbps up, you have gigabit down/100Mbps up Internet from your ISP. Correct?

That speed, 890Mbps, is not WiFi speed and will never be with Deco M5. I would recommend running speed test on smartphone wirelessly connected to Main Deco. Use Ookla speed test app, they have it for both Android and iPhone.

You should see WiFi speeds of 300Mbps-450Mbps, might be even less if there is lot of WiFi interference in your household. You need to run that baseline test to understand what is the true drop of WiFi speed on Satellite Deco comparing to Main Deco.

50Mbps on Satellite Deco will be down from the Main Deco WiFi speeds, not from wired speed of 890Mbps. 

Draw an imaginary line between Main Deco and home office, try moving Satellite M4R along that line and see if you'll find a place for M4R from where WiFi speeds in your home office are faster. This is all you can do with wireless Satellite Deco to improve its speeds.

The best you'll probably get in ideal scenario is around 200Mbps, but when you have walls, and you do, WiFi speeds on Satellite Deco will drop even further. 50 Mbps is not that terrible. 

You can get much better WiFi speeds than 50Mbps if you could wire Satellite Deco and place it in your home office. I am guessing you do not have Ethernet cable terminating in your home office, right? 

Do you have TV cable terminating in your home office or in adjacent room? If you do, Ethernet over coax is an option to consider.

Also, to exclude different content throttling/filtering settings in Deco that might impair WiFi speeds, I would recommend switching Deco mesh to Access Point mode. You can do that if you have router, not just modem, to which Main Deco is connected. See How to set up Deco to work in Access Point mode?

  @Alexandre. 

Thanks Alexandre for taking the time in putting together your reply – some great information there.

Quote: “If you see 95Mbps up, you have gigabit down/100Mbps up Internet from your ISP. Correct?”

Yes that is what I am seeing so I guess its asymmetrical fibre

I will try that Ookla speed test on the phone as you suggest.

I realise that 50Mbps is not too bad and I know there will be some drop off from the wired speed to the wireless speed.  I just think it’s a shame to have nearly 900 Mbps coming into the house and only getting actual usage of just over 5% of that speed.

I will try moving the M4R around – I have already tried doing that but I will look at it again.  Is using the Ookla phone app at the location (room) where you want to test the wireless speed the best way of checking the best location for the Satellite Deco?

I was wondering whether upgrading the two M4R’s to another model might improve things?? Or maybe keep them but add in more satellites??

I will also try switching to Access point mode as you suggest.  By doing this I will however lose Parental Control options which I do use from time to time to switch off internet access to devices used by the kids.

I said in my OP that the house is wired with CAT cabling – I think it might be CAT5 cabling (rather than CAT4 as I posted originally). The access point where the fibre cable enters the house and where my router and main Deco are set up are at the far end of the house from my home office.  This access point was where the original copper cable phone line came into the house (before fibre replaced it) and the original place for my router was in the home office where I had a wired connection to my PC.  In checking up online I see references to backhaul using cabling and the like but I don’t know enough to set that up and I am not convinced that it will help.

  @Arrowman 

If you have CAT5 cabling and can use it in your home office to connect Satellite Deco to it, the speed of WiFi will be much faster there than what you have now. See this document for discussion of using Ethernet backhaul with Deco mesh: General questions about Ethernet Backhaul feature on your Deco

You can use Ookla speed test app on smartphone to test what WiFi speeds you are getting from Main Deco. Obviously, you won't be getting faster speeds from Satellite Deco than you are getting from Main Deco, so it is baseline test to start with.

With Satellite Deco, if it is connected by Ethernet to home network, WiFi speeds nearby will be same as for Main Deco. If Satellite Deco is wirelessly connected to the Main Deco, expect WiFi speeds drop at least by half comparing to Main Deco. Add walls and such, speeds will drop even more.

These are limitations of wireless technology: you get more reliable WiFi signal by sacrificing WiFi speed.

You can switch Deco to Access Point mode to run speed tests to find what is the best you could get from your Deco in your house. After you've done with testing, you can revert Deco back to its Router mode if you need features such as parental controls. 

It is hard to tell what is the perfect location for Deco units, if upgrading them will improve WiFi speeds or if adding more units will make a difference. It all depends on specifics of house layout, and even such things as WiFi interference from household appliances and WiFi networks from neighbors. Which one can't measure unless they visit your house in person. 

That may be the reason you only see vague recommendations on how to improve WiFi speeds. 

You can google for general recommendations on how to deploy WiFi mesh or how to deploy WiFi range extenders - because, underlying technology and limitations are the same for both. When you search for WiFi mesh you'll probably find a lot of marketing talk, but searching for WiFi range extenders should give you more honest and technically sound articles and recommendations.

My recommendation would be to research if you can bring Ethernet to your home office. If you can, next step would be to connect Deco M4R to it and see if it can use Ethernet backhaul. If it does, the next step, if you want even faster WiFi, would be to replace Deco M5 and M4R with hardware that supports WiFi6. That will further improve WiFi speeds for wireless devices supporting WiFi6. 

Note that all this applies to any brand of WiFi mesh. If you decide to replace TP-Link Deco with different brand of WiFi mesh, you'll face same issues and challenges.

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If you don't mind to spend, and Ethernet wiring for Satellite Deco is not an option, you should look for tri-band Deco mesh hardware. For WiFi5 that would be Deco M9Plus, for WiFi 6 that would be Deco X68 and Deco X90.

If you want to try the best of the best TP-Link can deliver, replace your three Deco units with 3-pack Deco X68 or X90 and see if it makes the difference. This will cost you, and WiFi speed improvement is hard to predict. 

  @Arrowman 

I just thought of one more test you can do: bring Satellite Deco M4R to your home office and connect your PC to it by Ethernet cable. See if speed test on PC gives you better results with this setup. 

If it does, that means your PC WiFi network card contributes to slow WiFi speeds.

 @Alexandre. 

Thanks again Alexandre - you've given me a good few options there and I'll run those few tests and see what results I get.

When testing the WiFi from the Main Deco with the Ookla app should I put the other satellite Decos offline or does it make a difference?

I will have to look into making use of the CAT cabling I already have but I presume I'll need someone with hands on networking experience to set this up as it will likely need a hub or patch panel or the like  - as you can probably tell I am out of my depth at this stage!!

  @Arrowman 

 

When testing the WiFi from the Main Deco with the Ookla app should I put the other satellite Decos offline or does it make a difference?

Good point: makes sense to turn off Satellite Decos, to make sure mobile device does not switch between Deco units during the test.

Also, when you are doing speed tests on Main Deco, turn off 2.4GHz WiFi band in Deco app for Main Network. This is to force mobile device use 5GHz band exclusively. Dual band and band steering may cause WiFi performance issues. 

  @Alexandre. 

Ok thanks - I never use the 5 GHz band - its always the 2.4 one.

The 5 GHz never gave great coverage

  @Arrowman 

Arrowman wrote

  @Alexandre. 

 

Ok thanks - I never use the 5 GHz band - its always the 2.4 one.

This is the critical piece of information. In my tests with Deco M5 on 2.4GHz I have never seen speeds faster than 80Mbps, does not matter from where I ran those tests: desktop, tablet, smartphone. 

I don't know if I was just unlucky with every device I have using 2.4GHz, or it is something with my Deco M5, or what else. Because I have excellent 5GHz coverage all over my house, I turned off 2.4GHz. Just like on screenshot I shared, which is from Deco app on my smartphone.

Because of that, I can't speak of Deco M5 performance when running on 2.4GHz. My speed test results I shared are for 5GHz exclusively.

  @Alexandre. 

Ok - I should have specified that but it never even occurred to me.

2.4 GHz has been the "default" for WiFi for me in the house and I haven't even tried 5 GHz in a good while.

As I said earlier it might work reasonably well if you were beside the router but any distance away and the signal fell off a cliff.

My house has concrete block walls and a concrete slab first floor so maybe the "penetration" is not great on 5 GHz

  @Arrowman 

It's my fault: I should have asked. 50Mbps is good speed for wireless Satellite Deco on WiFi 2.4GHz. I suggest you still run speed test for Main Deco WiFi with 2.4GHz, I suspect you won't be getting more than 150-170Mbps. 

Wireless satellite Deco will cut that speed by half and more, so 50Mbps is withing expected speed range.

Ignore my recommendations about tri-band and WiFi6. They also based on 5GHz, which means if that band doesn't work well in your house, you won't have much better speeds from spending on that technology.

Your option is to see if you can get Ethernet to your home office and connect Satellite Deco to it. Unfortunately, other that getting Ethernet into every room where you want to have fast WiFi, there is not much else that can be done for the house with concrete walls and floors.