I have a tp-link vr600 modem router which has a 80mbs plusnet fibre connection. I'm testing on a wired connection with a windows 10 home built pc. My problem is I'm getting terrible speeds coming to all connected devises but according to my router the speed coming out of the wall socket is good, around 75mbps but when I run a Speedtest on my wired pc at best it will hit 35mbps and sometimes as low as 8mbps. I've tried everything, turning off wifi, changing ports, replacing router, replacing all cables, testing on different machine, line testing by openreach engineer and nothing has worked and it's driving me insane. Please can somebody who knows more about this stuff than me help me out before I go crazy!!