I have two generation 1 Apple TV's. One is dormant right now, not in use, the other is my primary unit for streaming to the main TV from movies and music stored on a MacPro. I also use this ATV to weekly almost rent a movie.
It has been great. Start rent, 32 seconds later, ready to watch.
One night my switch feeding the network to the entertainment system lost power. It took me a while to find it and in the process reseated a number of network cables. Finally it came on line. I use the network for device control with iRule.
Almost at the same time our Tivo in our bedroom started having network problems. This time in my reseating of the network cables this one got left out.
I also had replaced my sonicwall firewall with a wireless version. Lots of changes. But even before some of these changes and problems one night I went to rent "Cloud Atlas" and told my wife we could watch after dinner. So a few hours go by we sit down and I was shocked to see it saying it needed another 17 hours to download.
So we did something else. Ever since even though I've rebooted, reset networking, I've restarted the ATV many times downloads are just **** slow. I've tested my download speed over the LAN in general at 35mb down, 12mb up reliably. The only thing I need to try is to connect my laptop via wired connection to the small switch right where the apple TV is and try the download speed there. I don't expect it to be slow.
So what is causing the slow down? My ATV has a fan blowing on it keeping it cool while it runs. To save power I shut it down each time the system is shutdown so it is not running for long periods of time. But still even just now movies are taking forever to download.
None of the solutions in this thread have worked for me.