its because your computer specs just flat out aren't capable of streaming and running hammer and/or tf2 at the same time. it could also be an issue with your internet speed, go to this website and post your resultseverything is set up properly, its still butchering quality... it isn't working right. that what I mean.
it says my download speed is 15.33 Mbps
which is weird as my downloads run 1.2 Gbps