How many of you "put the hard discs to sleep when possible" ?

Discussion in 'macOS' started by Colonel Badger, Sep 29, 2008.

  1. Colonel Badger macrumors 6502

    Jun 30, 2008

    So i've just added an external HD for time machine and the spin up noise drives me nuts every 1 hour. I've moved the disk to somewhere where its at least a little better but anyway I was wondering whether to disable the "put hard discs to sleep when possible" ? tab to stop it spinning down (and hence stop the spin up noise since it'll always be spinning). I can't really hear the disk while its spinning! I guess unticking that might also improve response in general since the internal iMac disk will also NOT spin down. And here is where my worry is.

    If I disable the "put the hard discs to sleep when possible" the internal disk will be running constantly. Will this cause unnecessary heat to build up in my iMac?

    How many other people disable the disk sleep?
  2. wrldwzrd89 macrumors G5


    Jun 6, 2003
    Solon, OH
    I leave the disk sleep enabled. If you keep your computer running constantly because you have a scheduled task that runs when you're normally asleep, then I recommend leaving it on. Otherwise, it's perfectly safe to turn it off so long as the computer as a whole gets a chance to sleep.
  3. nanofrog macrumors G4

    May 6, 2008
    By allowing sleep, you reduce drive wear. It also saves power. :)
  4. Colonel Badger thread starter macrumors 6502

    Jun 30, 2008
    I was always under the impression that spin up/down causes more wear that constant spin !?
  5. miniConvert macrumors 68040


    Mar 4, 2006
    Kent, UK - the 'Garden of England'.
    Me too. I guess it's hard to know for sure. AFAIK HDD's are very happy to keep on spinning away.
  6. Colonel Badger thread starter macrumors 6502

    Jun 30, 2008
    Yeah. My main worry is the heat issue running the disk without sleeping in an iMac. Anybody have any experience doing this?
  7. allmIne macrumors 6502a


    Sep 17, 2008
    United Kingdom
    I put mine to sleep whenever possible; not that it really helps the pants battery life on my MBP anyway, lol.

    I don't really notice the spin up noise. That said, I usually have streaming, and the TV on, and live with my family, so it's probably the least invasive noise in my house at any given time :)
  8. mckyvlle macrumors 6502a

    Nov 21, 2007
    London, UK
    To be honest, I'm not even sure if that setting does anything on my MacBook. How does one tell whether the internal HDD is sleeping or not? That said, I have that check-box checked.
  9. richard.mac macrumors 603


    Feb 2, 2007
    51.50024, -0.12662
    i have it unchecked on my MBP as i dont want my external hard drive spinning up and down all the time as it makes a noise and momentarily beachballs.

    i sleep my MBP every night and during the day so having its hard drive spinning isnt much of a hassle as thats what theyre meant to do. plus i have it plugged in most of time. when im mobile i might turn it on to save some power.

    you can tell you hard disk has gone to sleep as youll here it spin up when you access it since thats when its the loudest.
  10. sickmacdoc macrumors 68020


    Jun 14, 2008
    New Hampshire
    To the OP- since you were originally talking about external drives, the externals from several companies (in particular the Western Digital MyBook drives in all editions) have the spindown built in to their onboard controllers and the "sleep hard drives when possible" setting has no control over that whatsoever. Western Digital confirms this in one of their tech notes on their site.

    At one point I had 5 of them and they were driving me nuts spinning down at different points so that one was either spinning down or spinning up almost all the time! :mad: I just created a little automator app that just wrote a little text file to each of them automatically about every three minutes or so (the same file being rewritten each time) and voila- no more spindown. Then later I tore them apart for the hard drives and tossed the cases! ;)

    Edit: BTW- spindown when in a long video render is a recipe for disaster when the computer expects to output to the drive and is asked for wait for it to get up to speed. Does not work well at all.
  11. nanofrog macrumors G4

    May 6, 2008
    If this is done multiple times a day, absolutely. Once a day however, isn't really going to hurt it. Consider the wear generated by 100% duty cycle vs. say 67% Duty Cycle (shut off for 8hrs/day). Comparable at a minimum I think. I've never had problems with this, but they were enterprise drives. Consumer models could be a very different story. :eek:

    To be more specific, most RAID cards won't actually allow sleep. I prefer models that support MAID functions, as they are better at saving power/reducing drive wear. Otherwise you have to manually shut down or just leave the system on.

    The power issue may not be much of a problem to some, but when you run enough drives, and they aren't needed 24/7, the power consumed adds up. Also keep in mind that SATA drives use a little less power than a SAS drive.

    It all depends on your priorities. :D
  12. Colonel Badger thread starter macrumors 6502

    Jun 30, 2008

    Yeah that's what I thought. The machine is used periodically through-out the day and thus the drives are spinning up/down multiple times a day. Looks like it would be better to disable the sleep.

    However I've still not heard from anyone re: temperature of a permanently spinning drive in an iMac?!?
  13. sickmacdoc macrumors 68020


    Jun 14, 2008
    New Hampshire
    Well regarding temps, that is going to vary all over the board depending on which Mac, which drives (even with a manufacturer's line the different models usually vary based on speed, capacity, etc.).

    For example the four internal drives on my MacPro currently read 82 & 84F for two Samsung F1s (1Tb and 750Gb), 104F on a Western Digital Caviar, and 114F on a Seagate 1Tb. The ambient room temp right now here is 75F. They all run 24/7 BTW.

    If you have not already, you might want to get ahold of iStat 2.0 or iStat Menus at or perhaps Hardware Monitor at to start tracking where yours run and what kind of a difference it even makes if they(it) do(does) spin down.

    it will, of course, only be able to monitor the internal drive temps that you asked about in your first post.
  14. nanofrog macrumors G4

    May 6, 2008
    You should be fine. Since they are passively cooled, I wouldn't want them to exceed 55C ever, and the cooler the better.

    From what I've seen from posted iSTAT Pro results, the HDD's run cooler than this. IIRC, the higher range is something around 46C. :) This is acceptable IMO.

    If you're worried, you could always use SMC Fan Control to increase the fan speed. ;)
  15. koobcamuk macrumors 68040


    Oct 23, 2006
    My iMac has been restarted only about 10 times in the past 2 years.
  16. pwn247 macrumors 6502


    Aug 30, 2008
    West Virginia, USA
    nanofrog suggested smcFanControl (free, from and I'm suggesting it too!

    If you're keeping your iMac's HD spinning permanently, take a look at smcFanControl to increase the fan speed a bit to keep the temperature down. You can use your iStats to monitor the temperature.

    In my Mac Pro, I have two hard drives, and, with the fans at their default setting, the HDs will typically run at a stable 85F (although the one in Bay #1 is usually a little cooler being next to that outgoing fan).

    So if you're worried about your iMac's internal HD overheating, increase the fan speed a bit. Never hurts to have a cool drive.

    And I've also heard from various legitimate resources that the drive spinning up and down all day will, indeed, ware it out; as opposed to letting it spin smoothly all day. After a few years it would seem that the little motor in there that spins the drive would certainly wear to a point that the drive would fail and need replacing.

    Look at servers- the HDs spin all day, and servers are typically very stable. ;)

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