Released June 2012 / Core i7 processor with Turbo Boost / Up to 1 GB DDR5 Video RAM

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Want to add in a second drive

I have an "Apple MacBook Pro "Core i7" 2.3 15" Mid-2012"

I've purchased this dual drive kit.

I, like OP, am wondering about the apparent 750 GB limit. Before my question below, can you remind me on the origin/reasoning behind the 750 GB limit?

Supposedly from what I've read, the mid-2012 MBP's optical drive can do SATA III (6 Gb/ps)... so does this change anything in terms of slapping on SSDs/HDDs over 750 GB?


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The limitation is physical size. While the dual drive carrier can only support a 2.5" drive which is not higher that the top of carrier frame.

So unlike many SSD's HD's are taller when you get larger storage space (larger than 750 GB). If you want you could go with a SSD like a Samsung 2 or 4 TB.

Otherwise OS-X/MacOS has no problem accessing larger drives until you get in the Exabyte sizes: Mac OS X: Mac OS Extended format (HFS Plus) volume and file limits

Now the rub! Some models of MacBook Pro's have issues supporting SATA III (6.0 Gb/s) drives. It makes no difference who's optical drive carrier you use as the issue is within the systems logic board. Review this: OWC Data Doubler to make sure your system is able to use a SATA III drive. If not you'll need to use a FIXED speed SATA II drive. This is where things get a bit messy. Fixed SATA II (3.0 Gb/s) HD's are getting hard to find. You will need to look out on the web to see if you can find one. Make sure you review the spec sheet for the given drive to make sure its a fixed speed drive.

For a long while we had auto sense drives like the older Seagate SSHD here's its spec sheet: ST1000LM014. As you can see in the line: Interface Access Speed (Gb/s) where all three SATA speeds are supported: 6.0/3.0/1.5 Sadly, Seagate no longer offers this drive. While you still can find one out in the wild it still won't work in your systems optical drive carrier as the auto speed technology will be confused. In addition the newer version of the Seagate SSHD the FireCuda Complete is only a fixed sped SATA III (6.0 Bb/s) drive and it too won't work in your system if it requires a SATA II drive.

This same technology is in many SSD's and likewise they won't work either in the optical drive carrier. This is why you need to find an older fixed speed SATA II (3.0 Gb/s) only drive for the carrier as outlined in the OWC Data Doubler dock you have one of the odd systems.

Update (07/26/2017)

@xilitive - If your current drive is dead you won't have an issue with the SATA speed problem of the optical carrier as you don't need it here.

I would recommend going with the FireCuda drive I spoke about its a very good drive and you can go up to 2 TB if you need that much space.

Just make sure you don't have the retina series system.

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My current HDD is busted and INOP, so in recovery mode (Command+R) I ran in terminal the following line “system_profiler SPSerialATADataType” and I see:

Link Speed: 6 Gigabit

Negotiated Link Speed: 1.5 Gigabit.

Is this information at all useful to see if that space is able to use the SATA IIIs?


On another note, I thought I had initially made this a comment. I guess it was converted into a question. Make it easily accessible public knowledge, I see. Thank you.


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