@HankRearden I wanted to let you know I found a fix over at https://community.tp-link.com/us/home/forum/topic/187958?replyId=466142

@Fjames003 

Thanks for reaching back out.  I too realized the problem was related to the teather app.  This was a deal breaker for me, because I needed to restrict some websites, which could only be done through that terrible app (which farms out requests to a third party and, if I remember right, is going to require a paid subscription to keep using, even though it cut my speeds in half...)   Anyway, I returned the router and went with a competitor and jumped into the world of DD-WRT (3rd party router software instead of the firmware that comes with the router) - more features, more control, less bloat.

If you want to stick with tp-link, you may want to look into 3rd party firmware packages (dd-wrt, OpenWRT, Tomato are some popular ones I've seen in my reading).  I think it's an obnoxious trend with router vendors to require using their cloud services for basic router management.  One, it's a security issue, and two, as we've seen with Teather, it's can really hurt performance.  So these 3rd party packages allow you to break free from all that and unlock your router's true potential.

@HankRearden thank you so much for the info. I will look into 3rd party software. It is truly unfortunate that their app is so bad. Hopefully in the future they can put out something better, because you're right it really is a security and performance issue. 
 

thanks again. 

@Carl 

I just tried it. It worked. For some reason I had one of my phone's set to high priority. I removed it and my speed went right up. Thanks.

@Carl 

This worked for me as well. I had a couple devices still set as priority, though dont recall why or how that happened. With QoS set to Standard and all device priority on my network turned off, I'm saturating my bandwidth and seeing identical speeds as if I was connected to my Fiber modem. Pretty impressive. 

May I make two suggestions?

1) This should be reflected in the manual or in the Web interface for the router. This is not super clear, and has a rather large impact on throughput.

2) It would be far simpler to just have an on/off toggle button that turned off QoS and disabled any priority device settings :)

Thanks for digging into this though. I really appreciate it. Its a great router, honestly.

@Fjames003 

Did you see the fix @Carl posted below?

@Carl 

This is not true, even my bandwidth is set to the maximum the router still limit download speed. Even if i give all priorities to device, service, etc.

I verify this just connecting straight to internet. 

This should be fixed asap!

Thanks.

BR,