I've got my Xbox One connected to ethernet and I usually get anywhere from 100 Mb/s to 1 Gb/s on my PC. Currently, I've spent over two weeks trying to download Halo Master Chief Collection and the bandwidth never raises above 400 Kbit/s with the average I see being closer to 15 Kbit/s.
Everything else runs fine, I can stream in HD on Twitch and Netflix with no issues, multiplayer in Advanced Warfare hardly ever hiccups, I just can't get the download speed to raise to appropriate levels. It's not only with the Master Chief Collection, I can't even get good speeds with any games from EA Access.
I've switched from wifi to ethernet, tried canceling the download, restarted the Xbox multiple times but to no avail.
Also, these are digital downloads, not disk downloads. I had no issue getting Advanced Warfare installed.