I have a flatmate, he likes to play LOL, we share the same router/internet. When I run the rig ( Nicehash ) his ping goes over 100 ( the game is not playeble ) . When I stop the rig, he can play. The issue is not about bandwith as I can watch youtube videos when he play without a problem. What can casue this and how can I solve?

Thanks in advance for the replies