Skip navigation

Dual internal hard drives in Mac mini?

8640 Views 9 Replies Latest reply: Nov 23, 2012 11:43 PM by Randy Knowles RSS
Randy Knowles Level 1 Level 1 (45 points)
Currently Being Moderated
Nov 22, 2012 12:38 AM

Hello all -


   I have a mid 2011 Mac mini, 2.7 MHz, i7, 8 GB Ram with the 7200 RPM Western Digital 750 GB factory upgrade drive.  (Macmini 5,2)  I'm planning to upgrade to a Solid State Drive (SSD).  My choice is to either install the new SSD as a second internal HD in the mini, or to pull the old conventional drive and retire it to an external enclosure, leaving the new SSD as the sole internal HD in my mini. 


   I'm familiar with the fact that my model has space for a second internal 2 1/2 HD, and also has a second SATA connector on the mother board.  I know that several places (such as iFixit and OWC) offer kits to add a second internal to my model.  I've seen statements in several palces that benchmark testing has established that which bay a drive is installed in makes no difference as to its performance, apparently either drive will work equally well in either bay position.


   So now I'm trying to decide whether to remove the mechanical WD drive to an extenal enclosure or leave it in.  My question is, will having 2 internal drives both operational degrade performance?  If so, any idea how much?  BTW my Mac mini model is SATA 3 6GB.  Are there any other factors to consider in making my decision?


   Thanks a lot for your comments!  - Randy

Mac mini, Mac OS X (10.7.5), (mid 2011); 2.7GHz i7; 8GB RAM
  • woodmeister50 Level 4 Level 4 (3,690 points)
    Currently Being Moderated
    Nov 22, 2012 2:16 AM (in response to Randy Knowles)

    Randy Knowles wrote:

    ...... My question is, will having 2 internal drives both operational degrade performance?

    There will be no performance degradation at all.   The SSD will much

    improve OS performance and can speed up any disk intensive apps

    if you put the data files on it while working on them.  The HDD will

    still be accessed at the same speed it was before.


    Also, some activities could be sped up if an app uses some temporary

    caching on the boot disk.  This is because it would be pushing data from

    one disk to another, instead of back and forth off the same disk.


    The only factor to consider in your decision is your ability to handle

    working with deilicate components.  If you have seen the videos on

    OWC for replacing/adding a drive in the Mini, it is not for the unskilled.

    Not sure how old your Mini is, but if it is still under warranty, doing the

    SSD install will void it.   So, if you break something, you will pay full

    price for any repair.

  • RRFS Level 5 Level 5 (4,425 points)
    Currently Being Moderated
    Nov 22, 2012 10:10 AM (in response to Randy Knowles)
  • VikingOSX Level 5 Level 5 (4,665 points)
    Currently Being Moderated
    Nov 22, 2012 12:37 PM (in response to RRFS)

    This would be true if the OP had stated he had a 2012 mini. His is a 2011.


    It does raise a question for the disk utility behavior in 10.8.3. Bound to bite a few unsuspecting people who do not want a Fusion fiasco.

  • VikingOSX Level 5 Level 5 (4,665 points)
    Currently Being Moderated
    Nov 22, 2012 12:52 PM (in response to Randy Knowles)

    The two things you need to bring to the SSD upgrade party is plenty of patience, and the OWC (macsales) Mac mini SSD drive kit. Oh, and a 9.5 mm, fast SSD compatible with Mountain Lion and with current firmware. The drive should be large enough that in operation, it is not more than 50% capacity, or slower drive algorithms in the SSD controller may slow the device down. That is the caution with my Vertex 4.


    I installed my SSD as a primary boot/application/user drive, and left the original 500GB drive in place. To uncomplicate having two drives mounted with OS X 10.8.2, I created an /etc/fstab file on the SSD that blocked mounting the original HDD on boot. Using Disk Utility, I can still mount/unmount that HDD any time after boot.


    There is no reason why you can't leave the original HDD inside the mini. On the otherhand, with a compatible external USB3 enclosure, it might find even more utility as a shared or backup device. I think once you tear the mini apart to do the SSD install, you may not want to do this again to remove the HDD.

    Mac mini, OS X Mountain Lion (10.8.2), • 8GB • Vertex 4 128GB SSD • 500GB
  • RRFS Level 5 Level 5 (4,425 points)
    Currently Being Moderated
    Nov 22, 2012 3:38 PM (in response to VikingOSX)

    I do believe that the 10.8.2 recent update (unknown build not 12C60) has been pulled as there are lots of posting indicating the inablilty to update to 10.8.2 from 10.8.1.. I know we don't speculate here but I'm guessing that Apple didn't want to make it possible for users to create their own Fusion Drives seeing as they can charge a premium for their proprietary drives.

  • VikingOSX Level 5 Level 5 (4,665 points)
    Currently Being Moderated
    Nov 23, 2012 12:38 PM (in response to Randy Knowles)

    Is the 50% parameter applicable to all bands of SSD's?


    This was a cautionary technical note for the OCZ Technologies Vertex 4. Read the details that OWC states for their drives, and the technical support section, for currency of firmware updates. I believe the 50% factor above may vary by manufacturer, and how they implement their controller firmware. Apple blocks TRIM support in non-Apple sourced SSD drives. Manufacturers get around this by implementing it in their controller firmware.

    You mention having 2 drives mounted under 10.8.2 being "complicated".  Since I am still on 10.7.5, I'm not familiar with this.  Is there some problem having more than 1 drive or partition mounted with 10.8?


    There is no functional or thermal problem with multiple drives spinning simultaneously. I had some issues with the App Store perceiving two different Apple ID when only one existed. This resulted in blocked app updates until I got it sorted. Your experience may be completely different.


    OS X running on the SSD will attempt to find things it deems missing on the OS X installation on the HDD. It may have been seeing two installation receipts, and two Keychains and got confused. The SSD was a current clean 10.8.2 install. The HDD had one OS X update on it to 10.8.2. Probably will never know precisely what confused it. Decided to leave the HDD unmounted at boot, but as yet, undecided about its future use.

    At present I don't know any way to make my existing Western Digital an external drive other than as USB2 or Firewire 800.  Am I missing something here?

    Those are the only two financially practical solutions. OWC resells a portable, external Thunderbolt drive consolidation solution by drobo. It is expensive. And of course, there is a Network Attached Storage (NAS) solution, by example, Synology DiskStation. There is one of these down the hall.


More Like This

  • Retrieving data ...

Bookmarked By (0)


  • This solved my question - 10 points
  • This helped me - 5 points
This site contains user submitted content, comments and opinions and is for informational purposes only. Apple disclaims any and all liability for the acts, omissions and conduct of any third parties in connection with or related to your use of the site. All postings and use of the content on this site are subject to the Apple Support Communities Terms of Use.