Twitch.tv and watching 720p+

I am just curious if this happens to anyone else but when watching some of the streams on twitch.tv usually on 720p+ its like the stream is in slow motion and on 360 its fine. My connection is pretty beast at least plenty for streaming and this only happens with a few streams most i watch are just fine and I have watched streams in 1080p perfectly fine. If anyone has any information or knows how to fix it any help would be much appreciated. Thanks in advance.