Just bought the AX50 ... Having the same issue on cable. The speed is limited to 100Mbps and directly connecting to my ISP router I get between 700-850Mbps.Issue is I never set up the device with Tether, tho I tried factory reset and didn`t help.

Any idea, if there is a solution or should I just return the router and get ASUS or smt? xD
Its idiotic that this issue is few months old, have several threads and no fix from TP-Link....

@Sevi HI everyone!

I have the same problem. The ISP provide 300Mb simetrics, and the speed provide for my router AX50 is 50Mb (download) and 5Mb (Upload).

I tried to factory reset and doesn't work. I don't have Theter App installed. 

Any help?

Thanks!

I am on 1gig internet. I have updated AX50 to firmware 1.0.8. 

I used to get close to ISP speed on my dell notebook with intel AX200. Now I am getting 450-500Mbps only.

I tried uninstalling teather app and did a full factory reset and configured using web interface instead of app. The results are still the same <500Mbps. I got AX50 from Malaysia

So far so good from me. Just need few tweaks on that.

System Tools > Internet Port Negotiation > 1000Mbps Full Duplex

Here few speed test tested on WiFi 6 devices and USB dongle as well

WiFi 6 Speed Test

USB Dongle

My internet speed is 800Mbps Download and 200 Upload. So i can get my maximum speed by using LAN and WiFi.

For WiFi the speed normally is between 400-600Mbps since mostly got wall/obstacle.

Ensure force the wifi to 160Mhz bandwidth. This help to maximise the speed. 

One more thing this through my experience during installation the WAN cable ensure not so long, limited to might be less than 3 meters is better. What i found, it tend to slow down your internet speed. This only applicable for WAN port to connect to your Fiber router.  For LAN port (p1-p4) are okay. Since the longest i connected is 20 meters to another hub. Below is my speed through network switch.

One more thing, i installed the router directly to the wall. Might be this can help. Again please don't use Smart Connect or else you'll get lowest speed.

Same here, I have an 80Mbs connection from my ISP and the speed from my ISP provided modem is correct, at 80Mbs.

Doing a speed check on the tp link admin interface ALSO returns 80Mbs, however, the actual wifi speed being output is currently 5Mbps.

I have tried everything in this thread, removed thether, factory reset, everything on the comment above this one, and nothing has worked so far.

@JoePena26 What is your WiFi device connected? Name and model. This help to confirm. Have you use another wifi device as well to test? Make sure you connected to 5GHz signal to confirm. 

@Husni I've tried all my devices:

Thinkpad P53- which has an Intel AX200

Google Pixel 3

iPhone X

Vizio and Sharp TV, can't recall the model names,

Thinkpad X1 Yoga 3rd Gen - This is does not have an AX enabled card

When going to a browser for all of them and doing a speed test, they all show 5Mbs or even lower, and so performance is really taking a hit.

I thought perhaps one of the devices is causing the issue, since there's more that I didn't list, so I disabled the 2.4Ghz connection, which left only my Thinkpad P53, and my Pixel 3 connected to the router on the 5Ghz signal. Same Issue, 5Mbs download speed.

My set up has the AX3000 set up as a router to my xfinity modem. Right now, I'm using the Xfinity modem since it's the only one outputing the full 80Mbs.

Doing a speed test from the tplinkwifi.net dashboard also shows that the router itself has the full 80Mbs, it's just not outputing that speed for whatever reason.

EDIT:
 

To add to this, I've also factory reset the router, both through the button on the back and through the admin dashboard, both times I left the SSID as the default in order for no other devices to connect to it, so that I could test it with only one device. This this not work either of the times I reset the router, it always returned 5Mbs.

@JoePena26 all the devices as mentioned should get max speed. One more thing, when you test speed try change the server location. What i noticed not all server able to work perfectly when using wifi connection. 

or you may try fast.com . 

you may check at your laptop ax200. It's the wifi speed between router. Suppose the speed able to hit your max internet speed.

Let me know if you want to know my router setting to compare with yours.  

Telegram : Husni_Talip

@Husni On speedtest.net, I've tried several of the servers liste, with all returning the same numbers, at most, going up to 10-12Mbs. The same goes for fast.com.

I would really like to see your settings, as mine are all set to default currently. Before, when I wasn't having issues with speed, I had QoS enabled with priority on my Thinkpad P53.