I recently bought a new router (Tenda F300), because the old one started failing. I set it up as usual, PPPoE and everything. Everything was working great until I turned on my wired PC and noticed that the WiFi speed drops down to around 1mbit/s. I tried absolutely everything from restarting the router to upgrading the firmware. Nothing worked, as soon as I turned on the PC the WiFi just drops down to 1mbit/s. Turning off the PC or just using the Sleep command fixes the problem. I thought I might be downloading something on the PC, so I searched everything, but even the Task Manager shows that nothing is using the internet. I looked at the router's log, no one was using my WiFi either, it's just me.