Your download speed is not limited SOLELY by the speed of your ISP, but also the speed of the server providing those files and its own ISP. IOW, you're only as fast as your weakest link, which might be something you don't even control. So if my upload speed is only 200Kbps, and you attempt to download a file from my server, it doesn’t matter how much faster your connection is, you won’t do any better than 200Kbps because *I’m* the limiting factor, not you.