So, I completely understand the value of putting a hard disk (specifically) to sleep in some cases especially in the pre-SSD days of the past. It can save power, lower noise and such. But in the case of modern systems that are increasingly SSD-based, does this option have any value at all?

My MacBook Air (2018) running Mojave (10.14.1) has “Put hard disks to sleep when possible.” checked off by default (in System Preferences > Energy Saver), but this system uses an SSD.

Is this option only focused on hard disk drives and ignored by SSD drives?

I can’t imagine the internal SSD would ever “sleep” but correct me if I am wrong.

In short, does the “Put hard disks to sleep when possible” option have any affect on SSD drives in macOS?


According to Apple:

Put hard disks to sleep when possible

This setting powers down the hard drive motor when you aren't reading or writing files from the drive. Solid-state drives (SSDs) don’t have moving parts, so this setting doesn’t affect Mac computers that use only SSDs to store data.

Consider deselecting this option if you have an internal or external non-SSD drive and you use apps—for example, pro audio or video editing software—that work better with continued read and write access to the hard disk.

Source: Apple: Use the Energy Saver settings on your Mac [Bold emphasis mine]

  • Well this is what I expected! So great news. The only question I have is whether Apple ever plans on changing the wording in the preference pane itself since pretty much all of the the macOS devices being sold nowadays are SSD based. – JakeGould Nov 11 '18 at 6:54

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