I have no idea if it's a QNAP-wide issue, or just some specific models, I haven't bothered to do that much research. I'm guessing that the discs WOULD spin down if you have that option selected if they weren't constantly being pinged a couple times a minute. That constant pinging is the part I can't seem to track down.

An excerpt from a post I was reading while researching this sums it up prettt well: "700 posts about spindown/sleep/standby not working in the QNAP HDD Spin Down Forum. No one seems to be able to resolve it. Qnap clearly couldn't care less."

The only solution that I've found that seems to work is to install some other operating system on it, which kind of defeats the purpose of buying a turn-key NAS.