Test speed of my network card
Solution 1:
You may only test the real speed in your local network by doing data transfer. There are many utilities for doing that.
Testing within your computer won't do it, as the localhost adapter
works within the computer's memory, doing in-memory transfers,
without using at all the network adapter.
The best you can do is open the adapter's Properties to find its rated speed. Or you may use PowerShell to get the speeds of all your adapters:
Get-NetAdapter | select interfaceDescription, name, status, linkSpeed