I have been having the exact same problem. 50/5 Internet, but like clockwork 7pm EST YouTube becomes unplayable at anything 480p+ with the rest of the internet being ok. It's only after midnight that YouTube's videos become viable again. -- "A woman never runs away, a woman never hides away in order to survive." -Ayumi Hamasaki from her song "Real Me"
Same problem here. Its not only youtube but most http downloads. Vimeo does this as well. All of it hovers around 300KB for me and my brother(different apartments)... After midnight everything goes back to normal. BTW, bittorrent traffic never slows down which i assume is because the hundreds of sources for traffic. It looks like they only traffic shape single streams of packets?