That Download.com page you gave shows the green Download Now button but there's a message under it, "CNET Secure Installer".
Did you download CNET's installer file? It is small and that could account for the apparent speed. You then run that and it downloads the software file for you.
If that is what it is, just be careful when running that file. It may offer you some additional option like a toolbar or similar. If you do not want that, de-select it before continuing.