Slow WIFI 5.0 speed on Deco X20

Slow WIFI 5.0 speed on Deco X20
Slow WIFI 5.0 speed on Deco X20
2020-06-11 13:50:50
Model: Deco X20
Hardware Version: V1
Firmware Version: 1.2.3 Build 20200330 Rel. 41081

Hi there


I have 3 Deco X20s and 1 Deco M5 connected via Ethernet backhaul via a switch from the living room.  The main unit Deco X20 in the living room is acting as a router to the rest of the 3 units in MESH Mode.


I have 1 unit of Deco X20 in my study room that has very bad wifi connection, less than 10 Mbps on speed test, connected to WIFI 5 Ghz.


When I reboot the unit in the study room, it will not connect via Ethernet backhaul, but connected via WIFI to my Master Bedroom, which is 5 meters away in my Apartment.


In addition, I have a 1 GB speed internet plan, but the max WIFI speed test that I got is close to 250 Mbps, directly in front of the router, is that reasonable?


Does anyone face slow WIFI issue with Deco X20? Seems like this new product is not very stable in terms of WIFI.


Hope that TP-Link support team cn help.




3 Replies
Re:Slow WIFI 5.0 speed on Deco X20
2020-06-18 13:50:27
but after some time the x20 at the study room will switch the connection to ethernet ? The wifi speed is around 250 Mbits - with a mobile phone or with a notebook ? What's the type of the wifi card in the client device ? What's the connection speed (not the speedtest results) of the client. Example : my Samsung A40 connects to x20 around 433 Mbps, my wife's huawei at 800 Mbps, My download speed is around 220-250, my wife's speed is around 400-470 Mbps. my desktop is using the tp-link Ax3000 pci card, and connects at 1,2Gbps to the x20 and the speed is around 860 Mbps. So the speed is depends on the client too.
Re:Slow WIFI 5.0 speed on Deco X20
2020-06-19 14:31:18 - last edited 2020-06-20 01:53:28



Thanks for the reply.


Yes after sometime the study room will switch the connection to Ethernet, it may take days for the switch to Ethernet backhaul to take place.  I am using a TP Link 8 ports switch. Have tried swapping the cable and ports on the switch, didn't help.


I speed test using mobile phone, Huawei P30 Pro, connected at 866 Mbps, WiFi speed still running at less than 10 Mbps.


I found out that when I disconnect the Ethernet Cable from Deco x20, my WiFi speed will be 100 Mbps on my Huawei.


Suspecting something wrong with my  Ethernet Cable that connects from the study room lan wall plug to Deco x20, I changed out to a new cat6 ugreen flat cable. The WiFi speed on Huawei mobile jump to 390 Mbps, but it was short lived.  I took the Ethernet Cable out again to shift the Deco x20 in position, and then plug in  the Ethernet Cable into X20. The WiFi speed drop back to 10 Mbps,  I changed cables multiple tikes, reboot X20, did not managed to bring the speed back to 390 Mbps.


Either my lan connection has a problem, or the X20 deco unit is unstable. I tried a Deco m5 unit in the study room with Ethernet plug in, I get less than 10 Mbps.


So I conclude the following:


1. It's a lan cable or wall socket issue 


2. It's a x20 firmware issue.


I shall plug a Asus router to my study room lan to try, if my Asus does not have low WiFi speed, then it's confirmed to be a x20 firmware issue.


Update: I swapped the TP Link X20 Deco with a Asus 87U router. I connected the Asus with the same lan cable, the Asus managed to hit 100Mbps consistently on Huawei P30 Pro, connected at 866 Mbps. Once I move the same lan cable to X20 Deco, the WiFi speed drop to 10Mbps, with Huawei P30 Pro connected to X20 Deco at 866 Mbps.


Therefore,  this seems to be a firmware issue with TP Link X20 Deco.


Hope that TP link engineer can look at my post and advice what other tests can be done to troubleshoot the problem.

Re:Slow WIFI 5.0 speed on Deco X20
2020-07-03 06:52:29


Sorry that I fail to reappear your problem in our environment

May you connect laptop to the low-speed deco with ethernet cable ,and test if the speed is that low as well,check if the link speed of lan is 1Gbps.

Additionally, does all decos besides main deco have low speed, is there any other problems like some deco blinking red.

Try test speed with all other traffic stopped.

If any deco besides main deco does not have the problem,try transpose each other.

Try check the linght of switch which indicates the ethernet link speed.

Try if reboot the main deco can help.

Thanks for your time.