So I have a gigabit connection. The setup is: ISP modem (DIGI (isp) oem Huawei, can't remember the exact model) that goes to an Archer C2 AC750 router. All 4 LAN ports are used on the router. I'm using CAT5e cables. On my laptop, I get the full speed, and have no problems with the connection, no matter the port on the router. But my other PC is only pulling 500-600 mbps at max in Speedtest. (Tested because downloads felt slower on that PC) The PC has an Asrock Ab350m-HDV motherboard. I tested the cable with my laptop, and it was pulling around 950 mbps as it should. Plug it back to the PC, now it's only pulling 200 mbps. I reinstalled all LAN drivers, checked the windows settings, cleaned the port with compressed air, but I couldn't find a clue why the internet is so slow. In control panel, under adapter settings the speed is 1 Gbps. Using task manager, there was nothing else using the internet when I tested it. Is there something I missed?