I have several drives solely dedicated to AVHD. With the iPad/iPhone client, the app would patiently wait until all the drives had spun back up before displaying the contents. On the ATV4 client, this wouldn't happen, necessitating manually traversing in and out of the various directories before anything would display.
Most modern drives employ their own energy-saving routines which seem to ignore the computer's own energy saving settings—at least on the Mac they do. Then I remembered a little application developed by Digital Heaven, purveyors of fine software for FCP and FCPX, which avoided exactly this problem when using those programs with large disk arrays. Essentially this program writes a tiny hidden text file to the selected drives at a user-defined interval (I use 5 minutes) in order that the drive remain active.
The difference is remarkable: where previously I had to jump through hoops to get AVHD to respond on my ATV4, sometimes even having to quit and restart the server, now it functions flawlessly. I have no idea if something similar exists for Windows, but for anyone using Macs with their video library spanning several drives, this program is a boon.
The app is called Disksomnia, and is available on Apple's App Store.