@Gusj 

You can't have 900+ download from Deco M5, it is not capable of that. Still, under 100Mbps is too low. Main Deco M5 should deliver up to 500Mbps, Satellites connected wirelessly to Main Deco will deliver less.

Here is test I suggest you do:

1. Configure Deco mesh to run in Access Point mode. You can do that if your ISP provider gave you router/gateway. Switching a Deco to Access Point (AP) Mode

2. Power off all Satellite Deco.

3. Make sure device you are running speed tests on is connected to Main Deco WiFi and not to some other WiFi.

4. Position device you run speed tests on at a distance of not more than 2 meters (6 feet) from Main Deco, with clear unobstructed view to Main Deco.

5. Run speed tests in that setup and share results here.

If you want WiFi speeds reaching gigabit, you should replace M5s with WiFi mesh, from Deco or other brand, that supports WiFi6 or better.

  @Alexandre. Thank you for your informative reply. 
I managed to get 400+ on a deco k5 guest network running on 5Ghz connection. 
unable to replicate  that on deco M5 default  WiFi network. Still getting 40 mps download and 75 upload. 
could it  be a hardware: firmware issue  or just software settings need adjustment ?

what reasonable model you suggest would be a good alternative to deco M5 mesh system that can go up to 900+ on WiFi  and cover the same area ? 

appreciate your feeback 

thanke 

  @Gusj 

Speed difference on Main and Guest network shouldn't be hardware issue: same hardware runs both networks. It could be settings, that's why I suggest switching Deco mesh in AP mode for troubleshooting purposes. In AP mode, there are practically no settings different between Main and Guest networks.

You could try to switch Main network to 5GHz only and see if it makes the difference:

When it comes to WiFi protocols, newer are usually faster but shorter range. Which means, you should not expect WiFi6 cover same range as WiFi5. What you should expect is at distance of 1-2 meters (3-6 feet) from Main Deco the speed of WiFi6 will be closer to gigabit, while WiFi5 could deliver just half of that. Move further and results will depend on distance and other factors specific to your place.

For replacement with WiFi6 Deco, I would recommend Deco X50 or X55. This model provides good balance between price/performance. 

If you like M5 form factor and/or need to wall mount Deco unit, consider Deco X50-poe.

You can mix those in one Deco mesh.

  @Alexandre. 

Thanks again for your reply.

my main network was set to 2.4GHz  I switched it to both 2.5 and 5 GHZ and my speed went up significantly

As you mentioned as well, the closer I am to the main Deco router the  higher the speed, but when I am closer to the secondary Deco unit, its not as fast as the main unit is that normal.

download Speed went up to 392  and  78 upload when using  2.5 /5 GHZ setting on iphone 14 while  being next to the main unit. what do you think is a good achievable  speed with Deco M5 with those  settings  and being close to main deco vs further away from it?  how high can it get with a 1GBPS connection?

Will it make much  difference if I upgrade  to  X50 or X55 as you suggested? and will l notice any significant  difference  worth upgrading to a new  deco system at those speeds 300 vs 500+ MBPS? specially  when the distance  affects the speed anyway?

Also when using 2.5 and 5 GHZ settings, is it the same as using 5GHZ setting?  does the device automatically connects to the faster speed?  how does that affect  the performance  as well?

Also what other models you suggest for more distance and speed as well? like AXE5400  , AX3000 vs X55 Xe75  as many models are on sale  for Cyber monday, Do you think its worth upgrading. I can't seem to tell the difference  between all those models and features 

Your feed back is appreciated

Thanks gain 

  @Gusj 

In my tests I have run with Main Deco M5, the best ever result I've got was 530Mbps. This is in almost ideal conditions, with no interference from other WiFi networks, and after literally hundreds of speed tests. That was with Pixel 7 Pro smartphone.

If you are getting close to 400Mbps, this is good enough. This could be the best M5 can do in your environment.

I am not sure if it is worth for you to upgrade to X50, it depends on your preferences, budget, etc. In my case, I went the opposite way: downgraded my Internet link from gigabit to 500Mbps. My ISP had very sweet deal on 500Mbps Internet for some reason.

It will be your decision to make.

Same answer for X50/X55. You will see improved WiFi speeds, especially near the X50/X55 units, but will it translate into better overall experience for you, I could not tell. 

When you have both bands enabled on Main Network, Deco will use band steering to recommend specific band for a device. For idle devices Deco will steer then to 2.4GHz, because that saves device battery. If you want faster WiFi speeds all the time, configure Main network to be 5GHz only.

There are about 30 different Deco models that support WiFi6 and I can't possibly go through them all listing their features. If you want very budget model, go with X20 but its WiFi speeds may dissapoint you. Top of the line would be X90/X95 - strong WiFi coverage with great speeds, but these are pricey. X50/X55 is in the middle and will provide adequate performance for reasonable price.

You will have to decide for yourself if you need faster WiFi speeds. Some people do, but if most you need is 4K streaming on single Smart TV or tablet, Deco M5 can handle that task just fine.

  @Alexandre. Thank you again for your feedback much appreciated

I think I will stick to my DecoM5 for now as I dont really notice  much difference when it comes to speed over various wirless phones/devices. 4K streaming is not my main priorty, I upgraded to 1G casue I got a great deal compared to 50 MBPS for higher price. 

So overall I am not looking for great pefromance over wifi, was just wondering if my DECOm5 is defected or not. as one of the Tech support guys said it was defected and needed replacment without even suggestign to switch to 5GHZ first to test the network.

I am assuming DecoM5 is doing its job within its limitation.

one last question, if I switch to 5GHZ only will it affect older devices connection in anyway?what steh diadvantage of using 5GHZ compared to teh combo of 2.4/5GHZ?

Thanks again for all you help

Best

Gu

  @Gusj 

If you switch Main network to only 5GHz, devices that can only use 2.4GHz will not be able to connect to Main network. If you know for sure you have such devices, keep dual band setting with both bands enabled. If you do not know for sure, leave just 5GHz on like in my example and see if any device at your place fails to connect. If they do, rollback to original dual-band configuration.

When both bands are enabled, TP-Link uses band steering. Suppose, you start active streaming on your smartphone while it is connected to 2.4GHz: it will eventually move to 5GHz when Deco notices consistent steady WiFi traffic with that smartphone. This saves smartphone battery when it is idle by keeping it on 2.4GHz, and delivers best speeds while smartphone is in heavy use.

Technically, it is sound idea, but for people who don't know how it works, and it is not properly documented, it could lead to some frustration. Example would be when you take smartphone from your pocket, where it were sitting idle on 2.4GHz band, and run speed test on it. Speed test load and duration may not be enough to force smartphone to 5GHz, so you are going to see speed test results over slower 2.4GHz - and be dissapointed.

I am also not sure how much battery will be saved by band steering. I turned off 2.4GHz on my Main network, so it is exclusively 5GHz. I see no issues with battery life for my household Google Pixels, Microsoft Surface tablets. Maybe for budget mobile devices TP-Link Deco band steering will make the difference, I can't tell.

  @Alexandre. Thanks again.

will test and see if it changes anything 

Much appreciated