Why is updating so slow?

[Gary Hodges]

I have an incredible connection at work.  Updating 100-200 MB is
painfull.  Not in a 56k sense, but it takes way longer than it should.
 The download speed is never constant either.  It will go from snail
to blazing and back to snail.  Rinse and repeat.  As an example, time
to completion will range from 5+ hours to 50 seconds depending at what
part of the cycle I'm on.