The question: Why is my Diablo 3 client downloader so slow?
The answer? A setting in Internet Explorer. This is exactly what I did to go from having my downloads languishing at 500 KB/s, and no data getting downloaded (strange, I know), to maxing out my connection.
Open up Internet Explorer, if you are not reading this from it, and go to tools->internet options->connections->lan settings.
Once there, uncheck the box that says "Automatically detect settings". Boom, instant super speedy download.
I hope that this has helped you in some way, and all my thanks goes to mrpudgy for pointing out this solution!
