There are too many possibilities to list here, but some are
A slow path from you to the server
An overloaded server
A slow path from your provider to you
Something wrong with the phone (that's usually the least likely thing when you have slow downloads - the phone usually either does download or it doesn't).
I'm not where you are, so I can't text from your cable to the server you're downloading from, but a few cross-country tests are telling me that there's a lot of internet traffic going around today (speeds bouncing all the way down to zero for moments), so I wouldn't worry about it until at least Monday night after midnight US time (any timezone - it's only 3 hours from coast to coast). That's usually a pretty low-traffic time.
05-28-2015 03:32 PM