If you are experiencing problems with streaming video on your Apple TV, you may want to take a closer look at your DNS settings, according to Mac developer Joe Maller. Maller recently rented an HD video via iTunes and was astonished to discover it would take two hours to download over a reasonably fast 15-20 MBps Internet connection. Maller searched for an explanation and stumbled upon other users who were reporting the same problem while streaming rentals. According to Maller, the problem occurs when you change your DNS settings from your ISP to a third-party like OpenDNS or GoogleDNS. When you revert your DNS setting to your ISP's servers, the problem disappears.
According to Maller's theory, Akamai is able to obtain the correct geography information and accurately route you through the closest server when you use your ISP's DNS settings. If you subvert this process using a third-party DNS service, then the routing from Akamai may be less than optimal. It may even route everyone through the same pipes which causes congestion and slows down streaming. While this intuitively makes sense, Maller only provides anecdotal evidence to support this theory. Until more evidence surfaces, I would not go around telling everyone they need to ditch OpenDNS or GoogleDNS. Nonetheless, this possible DNS effect is something to store in the back of your mind as changing your DNS is potentially a quick and easy solution if you are having difficulties while streaming Apple TV rentals.