It is common to replace a MacBook Pro's hard disk drive (HDD) with an solid state drive (SSD), however, that may pose a threat to the HDD if installed in the optical bay instead of the SuperDrive.*

Therefore, that leaves the option of:

  • Leaving the existing HDD where it is.
  • Then installing the SSD instead of the optical drive (SuperDrive) with a bracket.
  • While still using the SSD as the main boot drive.

Some websites mention that there may be issues with sleep and hibernation if this is done.

Is that true? Can it be mitigated?

Are there other issues with this approach?

* It could also mean that the HDD will be louder, since the main bay where it is usually housed has rubber to muffle vibration noises.

  • Can you share the websites that mention the issues with sleep and hibernation? I have my SSD in the optical bay, but get a weird wake-from-sleep bug that i haven't seen mentioned elsewhere. Dec 11, 2012 at 4:33
  • I read about them a few weeks back, doubt I'll find the exact ones — but feel free to Google and share the links here?
    – Baumr
    Dec 11, 2012 at 12:09
  • 1
    It will be interesting if any models of machines have low level connection oddities (like perhaps a drive temp sensor) that makes choosing one over the other preferable. I usually place the lighter drive in the optical bay since it's not as securely connected to the body as the intended HDD slot.
    – bmike
    Dec 11, 2012 at 16:42

2 Answers 2


I usually place the lighter drive in the optical bay since it's not as securely connected to the body as the intended HDD slot. This also plays into the rubber shock mounts for the HDD which both protect it from accelerations as well as isolating/dampening whatever vibration the drive motors cause.

As phrased, you may get a null answer since there may not be any issues with either placement. Macs can boot from external drives and have no problems writing the sleep image to an external USB or Thunderbolt drive since the OS wants to keep the system on one drive.

The only issues I've seen are people using links to place some of the core OS and support files on a secondary drive rather than just placing user files (home folders) and safer documents on a manual/fixed tiered storage system.

With core storage and Apple's broad support of any SSD to comprise a FusionDrive the need to micromanage what files live on which tier of storage might hopefully become a thing of the past.

  • Thanks, so there are no hibernation or sleep issues you've experienced?
    – Baumr
    Dec 12, 2012 at 15:49
  • 1
    None - but there are a lot of different models of Macs out and I've used maybe a third of the recent models. We also tend to get higher end SSD and when things fail - it's usually a warranty exchange and not that things don't work when initially installed.
    – bmike
    Dec 12, 2012 at 15:59
  • Thanks! Cool, I was asking so generally for everyone elses benefit and to conform with Stack Exchange standarbs, but I have a Late 2011 MBP which came with an Apple SSD plus an Apple HDD from another MBP. So should be fine, right? I'm still deciding on what kind of bracket to use... any advice?
    – Baumr
    Dec 12, 2012 at 16:23

Some Macbook Pros don’t have full SATA III in the optical drive bay so I opted to put my samsung 840 pro into the main bay to take full advantage of the speed.

On your mac, open up “system information” (applications/utilities/system information). Find "SATA/SATA Express” in the side bar. Click on the SATA Connection and see under “negotiated Link Speed” for your optical drive.

There is a slight hiss from having the HD in the optical bay, but it’s barely noticeable and it’s a WD Black 7200 rpm.

There are issues with hibernation but I just turned it off since I turn off my computer if I’m going anywhere far and boot times with an SSD are ridiculously fast.

  • I have Link Speed: 3 Gigabit | Negotiated Link Speed: 1.5 Gigabit for my optical drive and 3/3 for main bay. So it's better to keep my Samsung 840 pro in the main bay no question about it? I for WD Green 2TB as additional drive but I'm not sure if it has motion detection built in...
    – davidhq
    Apr 13, 2014 at 19:49

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .