2013 iMac external hard drive spin up?


macrumors regular
Original poster
Aug 24, 2008
Hello - In December I purchased a 27" iMac with 512gb SSD. I noticed that my Seagate 3TB USB 3.0 drive that I have connected goes to sleep randomly and when it wakes up, the drive takes a couple seconds to spin up and seems to slow down everything while its spinning up. I noticed that I can change the hard drive sleep setting here: http://www.thexlab.com/faqs/harddrivesleep.html but will this do any damage to my SSD? Is it OK that the SSD never goes to sleep? Are there other settings I should be looking into?

Thank you!


macrumors G3
Jul 30, 2003
An SSD does not spin, so would not have a delay to spin back up.
"hard drive sleep" settings should be ignored on the SSD. In any case, sleeping the SSD (if that is even possible) would have no discernible affect on your system, nor would it be any cause for concern.


macrumors 6502
Feb 2, 2013
It won't hurt the SSD. It may or may not allow the external drive to stay spinning. Some Hard Drive manufacturers set their firmware to automatically put the drive to sleep after a set period of time, and these won't be affected by the OS settings.

Other drives may adhere to the OS Preference Energy Saver setting, or the pmset Terminal command and not spin down. Also, many newer Hard drives seem to be able to accept the "Do Not Sleep" command better then when USB 3 was first introduced. You'll just have to see if it will work on your Seagate.
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