Just to follow up here... this is 100% an issue with the M5 Deco's. 

I've tested and tested and tested and I can't get any device to get a speed above 360mbps, when they all used to get the max speed of my connection (500mbps when connected to the main Deco unit in the same room). 

Can someon please advise what can be done to resolve this as I'm loosing a bunch of bandwidth for no reason.

@TP-Link_Deco Any upate here? I'm on 1.4.7 now and still no difference. My broadband just got upgarded to 1gig and I'm still stuck on the 360mb max wifi on my M5's! 

@TonyReilly Try these things:

- Turn off Anivirus

- Set the QoS throughput to max 1024 up/down. This will get you maximum throughput. Reboot the deco devices when you make this change as well. 

This brought my speed back to around 85% of the ISP download speed (450Mbps)

@pvdven Thanks.

Never had the Antivirus turned up.

Always had the QOS to the 500down 50up, but made the changes you suggested there and it's still the same.

It just seems odd that on 1.4.0 I was getting 500+mb when connected to main Deco, and now, consistently I'm only getting 360mb. 

I'm curious to see when I get my new modem and the 1gig connection will that increase, or will I still be locked to 360mb, cause if I am, I'll be returning these under EU rules that they are not fit for purpose and don't perform as advertised.

That or HOPEFULY @TP-Link_Deco might actually acknowledge there's an issue and inform us a fix is on the way within X time.

I'm on 1.2.4 (AP mode), wondering if it's 'safe' to upgrade to 1.4.7 now.

I only have a 100Mbps Internet connection.

@McFly If it was me, and things are working, I wouldn't upgrade. I'd love to downgrade if I could, but there doesn't seem to be any way to do that.

Hi @TP-Link_Deco ,

Screen shots attached. 540mb was connected to my modem, the 510 was connected to the Deco. 

The speed test in the Deco app, registers between 490 and 500 consistently. 

Main Deco is directly connected to my modem and is in, I think router mode. 

The 320mb result is connected to the main deco, in the same room, approx 6 feet away. Anything before firmware 1.4.4. i was getting the 500+mb in the exact same spot and since 1.4.4, I might get 360mb, if I'm lucky. 

QoS has always been set to standard and I've removed the high priority devices as well and I've set the total bandwidth to be available to be 1024 up and down (I'm currently on a 500mb package, but I'm just waiting for my 1gig modem to arrive)

Oh and I've figured out that I'm on a V1 deco setup.

Please let me know what further details I can supply to try and resolve this.

Kind regards,

Tony

@TP-Link_Deco Just to confirm, I have upgraded my modem and broadband account to a 1gig and the max wifi speed I'm getting is 360mb. The speedtest in the Deco app is reporting 900mbps down, so the speed is there, but something in the last couple of firmware updates is killing the wifi speed.