Make and model of your motherboard(networking card)? Might want to see what BIOS version you're currently on and if you have any BIOS updates pending. You will also need to check and see if you're on the latest version of Windows 10. Speaking of which, did you try manually reinstalling the drivers for your networking adapters(Ethernet port and wireless card) in an elevated command, i.e, Right click installer>Run as Administrator?
To figure out if this is a windows software issue or a hardware issue, boot up a linux live cd/usb and test there. If you get full speeds--windows software issue. If you don't get full speeds--hardware issue in the nic or network.