@Lera 

got the exact same issue seems a general problem with this model 

@Lera  Did you find a solution for this issue, I am having it too.

Thanks

Lera wrote

I have a TP-Link TD-W9960 router with the latest firmware. The router connected to the PC by ETH connection (wired). I have VDSL internet connection 40Mbps/3Mbps, however the real upload speed is 1.5Mbps - half (tested on few sites). When I connecte a router which was privide me by my ISP the upload speed is 3Mbps. I have replaced the router already, but the problem still there.

 

Any thoughts?