I think it has been said before but Streamboost or any kind of QOS is designed to create a bottleneck between your router and the internet. The purpose being is if the bottle neck is at your router, you can control it and design it to better work with your ISP. I saw this personally with the PS4 where it would show upstream packet loss unless I capped the outbound speed to a certain amount. Think of it like speed control on a car so that it starts and stops less on the way to its location, and thus making it take longer to get there.