HI. Why does it take me a minimum of 4 hours to download 1 tv series.

Slow Internet connection.

Define "good".

What is your actual Internet speed?

Test it at http://www.speedtest.net

That's actually rather slow...

For the best viewing experience when renting or purchasing iTunes content on Apple TV, you need a broadband Internet connection. A sustained 8 Mbit/s or faster Internet connection is recommended for viewing 1080p high-definition movies and TV shows, 6 Mbit/s or faster is recommended for viewing 720p content, and 2.5 Mbit/s or faster for standard-definition content. Internet connection speeds may vary depending on your ISP and other factors.

High Definition vs. Standard Definition

If your Internet connection is too slow to quickly start playing High Definition movies or TV shows, consider changing your iTunes Store Video Resolution preference to Standard Definition. To do so, from the main iTunes menu, choose Settings > iTunes Store, and toggle the "1080p HD" or "720p HD" option to "Standard Definition". Movie and TV show purchases and rentals will now be in Standard Definition.

Note: 1080p HD content is available on Apple TV (3rd generation) only.

Consider paying for a faster connection. Remember, if you're in a neighborhood or apartment building, you're sharing the bandwidth with all of your neighbors. You might do better therefore by downloading in the wee hours of the morning.

My download speed, for example, is about 52,000 mbps--but I still notice a difference in speed between at dinnertime, when a lot of folks are home using the internet or streaming TV, versus at dawn, when very few ppl are online or streaming.

Paying for this level of speed is well worth it for me, with a large household and up to 14 items online at one time. I also wanted to be able to stream to two or more devices without interruption. This enabled me to stop paying for satellite TV, so that I am actually paying less per month than when I had 20,000 mbps plus satellite. Works for me, YMMV.

Good Luck!

Kate