I've seen several reports that once you get your normal console update, the in-game update goes slower then 1mb/s no matter how fast your connection is.
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Same for me until around 40 or 50% then it went really fast. Also annoying that if you leave the game it doesn't keep doing the download, so if you go off and play something else (like I did), thinking it'll just keep downloading in the background... it doesn't.