Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Level 1

49 points

How do you turn off/spin down an iMac's internal hard drive?

My iMac is about a year old and the internal hard drive makes an annoying high-pitched whine that's pretty normal for older drives.

No problem, I connected an external SSD via USB and boot off of that. It's nice.

The problem is, I can't figure out how to turn off/spin down the internal drive. Here are the things I've tried:

1) You'd think just dragging the drive to the trash can (in the Finder) and thus unmounting it would cause it to spin down. It doesn't.

2) You'd think that enabling "Put hard disks to sleep when possible" in System Preferences would eventually spin the drive down especially because it's unmounted and therefore must be idle, but it doesn't.

3) I did find one way to spin down the drive (after one minute, at least) using the following steps:

Use Disk Utility to mount the drive and unmount it again

Use this Terminal command: sudo pmset -a disksleep 1

Unfortunately I have to repeat these steps every time I boot the computer or wake it from sleep, which is a huge hassle.

Any help with this problem or just information about it is greatly appreciated! Ideally it seems like there must be a magical command line to run or file to edit such that the drive will spin down when unmounted. Crossing my fingers.

iMac, OS X Mountain Lion (10.8.2), 27", 2011

Posted on Oct 29, 2012 4:38 AM

27 replies

baltwo

Level 9

62,362 points

Oct 30, 2012 2:22 AM in response to motrek

motrek wrote:

My iMac is about a year old and the internal hard drive makes an annoying high-pitched whine that's pretty normal for older drives.

Interesting. The Seagate in my iMac (late '09) is quiet as a mouse. I can't hear reads or writes. Do note that that goes for the Seagate 1 TB HD, model ST31000528ASQ, revision AP24 that failed in April and the replacement model ST31000528AS revision AP2E. If yours is a 1 TB Seagate, I suggest that give AppleCare a call and see what they can do for you.

motrek Author

Level 1

49 points

Oct 30, 2012 2:57 AM in response to baltwo

Unfortunately my iMac isn't covered by the recall.

As for whether or not your hard drive is quiet, a lot of it comes down to the environment you use it in and possibly how good your hearing is, since we are talking about high frequencies (7200 Hz and maybe harmonics at e.g. 14400 Hz).

For example, in my quiet apartment late at night, the whine is very noticeable and annoying to me. But I'm sure I wouldn't be able to notice it in a commercial building and especially not at or near an Apple Store.

Since most computers are much louder and make equally annoying sounds, you might think I'm being picky, but since I went to the trouble of buying and connecting a silent SSD I don't think it's unreasonable to want to deactivate the internal hard drive somehow.

baltwo

Level 9

62,362 points

Oct 30, 2012 3:17 AM in response to motrek

I realize that you say it's not covered, but if it's one of the original Seagates, you might have a case and might be able to get it attended to. Your choice whether or not you pursue the matter. I have normal hearing, usually 0-15 dB across the tested spectrum of 500-6000 db. I'm in my early 70s but have no hearing issues. Late at night in my home, the only place I compute, I only hear the G4's fans (very low and unobtrusive air rush) and nothing from the iMac. Run the pmset script as a login hook and that should take care of your problem. 😉

Jeff Shenk

Level 4

2,993 points

Oct 30, 2012 6:06 AM in response to motrek

Not to question the fact that you hear a highpitched whine, but you do realize that a 7200 rpm disc is spinning at 120 Hz?

RRFS

Level 5

4,522 points

Oct 30, 2012 6:16 AM in response to motrek

Have you considered having the SSD installed where you would get the performance you paid for? As a USB drive its response won't even equal a very slow internal SATA, Seems a shame to have it hooked up and not even as a FireWire drive.

MichelPM

Level 10

80,980 points

Oct 30, 2012 7:56 AM in response to baltwo

That's what I was trying to tell the OP. My drive in my 2009 iMac is pretty quiet with no high pitch whine.

Despite no weird sounds or SMART errors, my drive has been flagged for replacement.

The drive is still working fine.

There is a problem there with the OP's drive despite what the OP says or writes.

MichelPM

Level 10

80,980 points

Oct 30, 2012 8:00 AM in response to motrek

I Am thinking the reason the internal drive is still running is that Spotlight is still trying to index or search that drive.

As another poster pointed out, you need to disable the drive from indexing in Spotlight's Preferences.

Maybe this would keep the drive from spinning up?

Not Sure.

Oct 30, 2012 10:04 AM in response to MichelPM

Motrek, if you no longer want to use the internal drive anymore why don't you open up your iMac and remove it and replace it with your SSD.

baltwo

Level 9

62,362 points

Oct 30, 2012 11:18 AM in response to MichelPM

MichelPM wrote:

Despite no weird sounds or SMART errors, my drive has been flagged for replacement. The drive is still working fine.

The recall is for all of those, whether or not they're failing. Mine went in April and apparently they and Seagate identified the flaw causing the failures. So, the recall allows for a new one and ample time to prepare for restoring your current setup. I had eleven volumes on mine and restorable clones (also backed up), so restoration was a simple matter of formatting the new one and restoring. BTW, it was replaced onsite under AppleCare.

motrek Author

Level 1

49 points

Oct 30, 2012 12:03 PM in response to JShimazaki

@ JShimazaki: I would like to replace the hard drive with the SSD. I have been nervous about this since it sounds easy to get dust and fingerprints on the glass or screen but I will likely bite the bullet and give it a shot soon.

@ Jeff Shenk: Good point re: 120 Hz.

@ MichelPM: I don't see how it's possible for Spotlight to index a drive that isn't mounted.

@ RRFS: Actually, an SSD via USB is hugely faster than a hard drive via SATA at everything except transferring large files around (since USB 2.0 is practically limited to ~20 MB/s whereas hard drives can transfer ~120 MB/s sustained). But booting and starting programs is dramatically faster. If I decide not to replace the hard drive with the SSD then I will likely get a FireWire enclosure for my SSD to get it up to ~80 MB/s...

RRFS

Level 5

4,522 points

Oct 30, 2012 12:50 PM in response to motrek

Actually I have had my SSD in All 3 configurations while I was formatting it and transferring files around to get the setup how I wanted it. My internal regular HD booted in about a minute and 20 seconds, In fireWire 800 mode SSD booted in just under a minute, in USB mode SSD took well over 2 minutes and installed SSD takes 25 seconds. Not sure how you are making comparisons, mine were with a stop watch and the actual setup.

motrek Author

Level 1

49 points

Oct 30, 2012 1:24 PM in response to RRFS

Maybe improvements have been made with ML or maybe your 2 minute boot was caused by OS X rebuilding kext caches or finishing up the install of an update or something but I just timed my boot and it's 44 seconds. Not blazing fast but it's faster than I remember with the hard drive. Also, with the hard drive, it took 7-8 dock bounces to start XCode whereas with the USB SSD it's about 2 bounces. Similar performance improvement for running Photoshop and other programs I use frequently. Anyway, of course using USB for your main drive is not ideal but it's not really bad either.

How do you turn off/spin down an iMac's internal hard drive?