Late 2012 iMac 27” SSD

Well, I finally decided to upgrade the Fusion Drive in my Late 2012 iMac with a new Crucial SSD. The process is a bit daunting, but I think if I take my time I can do it. Here is what I have done in preparation for the upgrade which I will do later this week.


The Fusion Drive

I have not performed these steps yet, but here is the plan of attack. Before you can take the iMac apart and install the new SSD you should separate the Fusion Drive in the machine. The Fusion Drive is a logical volume made up of an SSD card and a spinning hard drive. It is fairly fast, but not as fast as a bare SSD. There are instructions at various places on the web on how to separate the Fusion Drive using the Terminal application. If the Fusion Drive is the main boot drive on your machine you should boot into Recovery Mode (Command-⌘ + R) and use the Terminal app from there. This next information is very important. When the Fusion Drive is separated, both the spinning HD and the SSD card are erased and formatted as separate drives! So, you will need to backup, backup, backup your stuff!

Once your stuff is backed up and you have split the Fusion Drive, you are ready to install the new SSD.

Tools & Parts

Besides a #9, #10 Torx screwdriver and a Spudger you will need the following parts to make this work. They are not all necessary, but this is what I will be doing.

Display Glass Take Apart

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Those are the strips to reinstall the glass over the Display. If you look closely you can see a little wheel with a handle on it which is for separating the glass from the adhesive strips attaching it to the Mac. Also, you see the credit card item for further separating the glass from the adhesive strips.

Imac Wedge

iMac Wedge
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Many Mac techs use this iMac Wedge. With the iMac sitting upright, you place this between the Display and the iMac stand. It supports the iMac while you work on it.

SSD Mount Bracket

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Because the SSD (2.5”) is smaller than the spinning hard drive (3.5”) you need a way to mount it in the machine. You attach the SSD to this bracket and then attach the bracket into the normal install location in place of the original spinning HD.

SATA Heat Sync Cable

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This is a very important cable. You need a special connector to connect the SSD to the SATA cable inside the iMac. Please note the long, thin wire with the little circuit board at the end. This is a heat sync that has to be stuck to the SSD after it is installed. If you don’t connect this cable (at least on 2012 and 2013 iMacs) your iMac fans will run out of control.

The most difficult part of this install is removing and reinstalling the Display glass. It is tricky, you must be careful not to break the glass. Also, since I moved my Photos Library off my main iMac to an external USB/SSD I really only need a 1 TB SSD for the install. The total cost for all this stuff will be around $300, perhaps a little more. That is pretty reasonable compared to a new iMac at about $2,000. I should be able to get 3-4 more years out of this iMac so I think it is worth the time and money.


Well, I will let you know in a couple of days how this goes. I am sure I will have an article or two on the actual install. Keep your fingers crossed for me.