@makellan 

What mode are you using the Deco in?  Also is the Deco acting as the router or just as a wired and wireless AP?

@Carl 

The Deco is a wifi router.

Mesh mode is on but my tests are from the unit pluged directly into the cable modem. I've tried turning off mesh as well.

@Carl 

Hi, any thoughts?

@makellan 

Have you ran a speed test from the main unit via the Deco App?  What were the results?  When you test on your device are you using the same test server?

@Carl 

When I run the test from the app to get the speed that the router is seeing through the modem, I get 300-350Mbps.

When I run the speed test from anything going through the router (wired or wireless) to the same speed test site, I get ~125Mbps.

@makellan 

Are the device test from the main Deco or the remote ones?

@Carl 

I've added highlighting to the original post as it's answered your recent questions. Is there a way to chat directly without posting on the forum and waiting for a response?

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Model: Deco M9 Plus

Firmware Version: 1.4.3

Much like the old thread, https://community.tp-link.com/us/home/forum/topic/152513, I'm getting solid 350+Mbps on a speed test from the Deco app but ~125Mbps to any devices.

The firmware is up to date.

I've tested devices:

* Ethernet connected to the main Deco

* Wifi connected within a foot of the main Deco

* Wifi connected to the main Deco with 2.4GHz turned off

All tests return very reliable ~125Mbps.

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I've tried these tests with and without a second Deco in mesh. All speed tests are consistent at ~125Mbps.

@makellan 

Chat support is available through our website. I will forward this additional information to our testing team, however please let me know if you prefer to contact the chat support team as I would want to avoid two teams doing the same work. 

@makellan 

Good to know.  in my experiance QOS typically only affected wireless devices and to the remote nodes so its good to know for future.