@dracktw thank you so much for that last picture!  It's true, pictures really are worth a 1000 words!!!  They kept talking about setting QoS & I would click the pictures & slide the controls, but nothing seemed to help.  Then I realized, after looking at your picture, that those numbers up top weren't just what my last test showed, they were the values being used for my QoS (which were set after a really bad test evidently).

After manually bumping those number up, my speeds are doing MUCH better!!!

@azzi9 

I'm following this thread because I've done everyting you all have recommended on here and still get 400mbps MAX on Cox Communications Gigablast. I cannot figure out what in the world the problem is! I have a 4400sqft house and this router defintely doesn't do as well as advertised for a large home. I think I'm gonna get a new one at this point. 

@BigRed2021 Same here was working great for a while then no luck. Stuck at 2.35 down /30 up and down when using the Archer A20. When connected to my Comcast modem with my laptop via cable 900 down/ 40 up

@azzi9 This adjustment did it for me as well. I was about to ditch my router!

I now get up to about 940mbs download on wired and greater than 640mbs on a 5G wireless connection.

@dracktw @JRice  just wanted to send along my thanks as well. Recently got fiber 1Gig Up/Down and couldn't get past the 450 Mbps cap on my LAN ports. Speedtest on the router side always seemed to come back with the correct speeds. 

Updated the router firmware and used the manuall QoS to set download and upload speeds and BOOM - seeing Gig over my LAN ports FINALLY. Glad I stumbled across this thread - TP Link should really consider documenting this better (seems like a software bug honestly) 

@JRice I've recently had similar issues.  I get 500G synchronous fiber service.   Directly off the modem I get steady 500-650 MBps depending on the time of day. However off of my router, wired or wireless, I am getting 124MB down and 12 up.  Then when I run speedtest directly on the router, through the TPLink interface, I am getting a constant flux of 5kb-146kb ps up and a solid 10-12 down over the course of a few minutes.  I have disabled all security and services and dropped all devices to verify no load pull on the router.  I have replaced the ethernet cables between the modem and router and the modem and my laptop.  It did not resolve the issue.

Aside from hardware failure, I'm not sure what else it could be.  

@mcdanielp3957 

What Router?

Does it have a SPEED setting on the QoS page?

If it does, there might be 2 possible settings, one for you to set it manually, and another to use the SPEED TEST data you saved from the Router Speed test.