What could happen to my internet?

Question

Computer networks

More recently, I had 100 Mbps Internet on 2 PCs. Now, one is 200 bps, and the other is still 100 Mbps. Help, where could the problem be: in the PC, in the router or with the provider?

Network card - Realtek Gaming GbE Family Controller
Router - Archer C50
PC connected via Ethernet

There is a switch between the PC with poor internet speed and the router

Answer 1

Well, apart from the fact that TPlink is not really a router in principle ...
Change the port for this cable on the router, plug it into another hole.
On the PC, in the device manager - remove the network card and restart the PC.
Check what happens
I hope it's not worth it to "optimize" the network card? Which comes from the manufacturer of the motherboard ....