Just gotten this 10GB network card from Amazon and after installing and running speed test on my 1 gigabit fiber connection. My download at 1GB, but my upload was 0.11mbps and lower pretty low. My previous 1GB network card tested 950mbps down, and 780mbps up. 

       I had installed official drivers off TP-Link download center for TX401 for windows 10.

      I found previous forum about this issue at https://community.tp-link.com/en/home/forum/topic/270248. One guyed talked about replacing cables and others talked about using Marvel drivers. Initially I done lots of things like changing pcie slots, cables, etc. They did not help at all. 

     Went to install Marvel drivers worked fine now getting 1GB down and 800+mbps up. Talked live with the tech support and mentioned to them their driver are broken they need to fix the issue.