Very slow hard drive - How to diagnose?

Discussion in 'iMac' started by T'hain Esh Kelch, May 22, 2014.

  1. T'hain Esh Kelch macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
    #1
    I have a 2011 iMac, quad i7 with 8Gb RAM and the stock HDD. I have trouble with my harddrive being excessively slow, and I am not sure if there's something wrong with it, or if it is the system. I have checked Apples call back for certain 2011 iMac HDDs, and mine is not one of them, based on the serial number.

    When my iMac has been asleep, and I wake it up. The machine is *extremely* slow whenever it needs harddrive access (Open/saving files, open/closing programs, accessing Spotlight, etc.), and this can go on for up to 30 minutes (!), and usually takes at least 10 minutes. Even opening a tab in Safari can take ~5 seconds, and entering a website adress and clicking enter, can lead to a ~5 second wait until it finally registers and starts loading the site. Starting a new application can take up to 5 minutes. Spotlight is practically unuseable as nothing loads.

    While it is going on, I can clearly hear the HDD working (No clicking, just the usual noisy I-am-working HDD sound), so I am certain that the drive is the cause. When it is done doing whatever it needs to do, the noise stops, and my computer becomes 'fast' again, ie. things open in a couple of bounces, Spotlight is instantaneous, etc. The situation is the same, albeit takes even longer, if I do a fresh boot of the computer, as it also has to load everything from the start that was open before.

    I have tried to do my own damage control and see if it Dropbox, in which I have 35Gb files and would be a likely culprit, but that does not appear to be the case. Otherwise I am pretty clueless as to what can be the cause.

    I usually have 100+ Gb space available on the HDD, and around 2Gb free RAM (Mavericks). Also, programs that are loaded into RAM, are usually quite responsive (Apart from when they access the HDD; as described with Safari and Spotlight above).

    Are there any programs that let me check what is writing/reading from the harddrive? Activity Monitor is not very helpful in this aspect, and in most cases the read/write activity is quite low when this is going on, which is puzzling. I am starting to think that my HDD is failing. I will be upgrading to an SSD when the next generation is announced, but I would still prefer not to have a failing HDD of course. :)
     
  2. rambo47 macrumors 6502a

    rambo47

    Joined:
    Oct 3, 2010
    Location:
    Denville, NJ
    #2
    You can try repairing permissions through Disk Utility or through the Terminal with the following command:

    diskutil repairPermissions /

    You can simply copy/paste the above command into a Terminal window. With some problems the Disk Utility can fail to open or fail to operate. The Terminal always gets it done.
     
  3. macthefork macrumors 6502

    Joined:
    Feb 2, 2013
    #3
    You can download "Blackmagic Disk Speed Test" from the App store.

    Also, check that the "Put Hard Disk To Sleep When Possible" box isn't checked in your Energy Saver System Preferences. If that box is checked, it can really slow things down every time the disk has to spin up.

    You can also go to Disk Utility and Verify Disk, to see if it catches any errors.
     
  4. keysofanxiety macrumors 604

    keysofanxiety

    Joined:
    Nov 23, 2011
    #4
    Check the hard-drive by downloading a program called Smart Utility (can be found here: http://cloudfront.volitans-software....utility311.zip) This will check the SMART data on your hard-drive which will very quickly diagnose if it's failing. If it comes up with a warning, hard-drive's knackered.
     
  5. yjchua95 macrumors 604

    Joined:
    Apr 23, 2011
    Location:
    GVA, KUL, MEL (current), ZQN
    #5
    There's your answer.

    Download Blackmagic Disk Speed Test off the App Store. If it's below 100 MB/s, there's your problem.
     
  6. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #6
    Start Activity Monitor and see if anything in the CPU tab is hogging all the CPU cycles. Also check the memory tab and look at the bottom and see if memory pressure is in the green (this is on Mavericks). If neither of these two items shows a problem, I'm going to say you have a failing hard drive.

    No way even the slowest and crappiest hard drive with be as slow as you describe when functioning properly.
     
  7. ticotoo macrumors member

    Joined:
    Jul 8, 2010
    #7
    very slow HD & solution

    Typically that is a symptom of a failing HD. Its a pain to replace in the 2011 iMac. Check OWC for replacement kits & instructions. I have a 2011 21.5 iMac & its always been slow, but not like you described.
    My solution was to get a Rocketstor 5212 & a Samsung SSD 940 EVO 500mg.
    the Rocketstor is a thunderbolt only drive cradle with 2 bays. So I use the external SSD for the boot drive & the other bay for a large HD. You can even raid the 2 drives. I got a significant increase in speed:
    Black Magic
    Rocketstor & SSD ~560 mbs
    VoyagerQ & SSD USB3 252
    VoyagerQ & SSD FW800 84

    Feel like a new machine :))
     
  8. T'hain Esh Kelch thread starter macrumors 601

    T'hain Esh Kelch

    Joined:
    Aug 5, 2001
    Location:
    Denmark
    #8
    Thank you guys.

    Smart Utility informed me that everything was fine.

    This is 25 minutes after a fresh boot, with the harddrive silent.

    If I do while it is chucking away, I reach 5-40 MB/s on both read and write.
    [​IMG]

    98% CPU free, around 5 minutes after a fresh boot. Hardrive keeps chunking away though. Screenshots here are taken 25 minutes after a fresh boot, when the harddrive finally stopped doing whatever it was doing (Notice the flat read-line). I guess the 7.2 GB stuff that has been read must be the problem? What could potentially be that large? I have Safari, Mail, Dropbox, iTunes, iMessages open, along with the apps used for screenshots.
    [​IMG]


    I already bought a OWC kit. I am just waiting for Samsung 850, or whatever they'll release soon (I hope!).
     
  9. Weaselboy Moderator

    Weaselboy

    Staff Member

    Joined:
    Jan 23, 2005
    Location:
    California
    #9
    You have plenty of memory, so that's not an issue. Try to look at CPU while the hard drive is thrashing around and look in the CPU tab to see if any one process is running high CPU usage.

    Also, try a safe mode boot and see if it does it then. A safe mode boot runs a stripped down system and by passes and login/startup items and can be helpful troubleshooting if this is a misbehaving app.
     

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