New PC and now bad LAN connection. What to do?

El
1

I have assembled a new PC… And now I have a very bad LAN connection. I use your Dlan from Tp link, which supports 100 MB / s. In addition a CAT.5 LAN cable. On my old PC and on my laptop, 63 mbit / s arrive via the dlan. However, on my new PC only 0.5 or less. I need help I don't know what to do…

Ce

Have you already downloaded and installed all drivers from the mainboard manufacturer's website?