Upgrade iMac to Fusion SSD for Speed

TechDC iMac 27” 2017  HDD to SSD (should work if there’s no fusion too)

I recently upgraded a 2017 iMac with a Fusion drive (SSD plus hard drive) to an SSD only Fusion drive by replacing the hard drive (HDD) with an SSD. While the idea of a fusion SSD may sound weird, it works great. The SSD in iMacs (especially 2017 and beyond) are much faster than a standard SSD, so you still get the fusion benefit of combining a faster and slower drive. And replacing a HDD with SSD is a huge speed improvement that can make a computer feel much more responsive.

Parts List

Crucial 2TB SSD ($207) – this is a hair faster than the Samsung.  


Samsung 4TB SSD ($400) – not a lot of 4TB options on amazon

iMac adhesive strips + opening wheel

Generic phone and iMac work kit (has the necessary plastic cards and scraping tools and many other parts not used)

3M pads to adhere SSD inside iMac

Preparation Steps (note that a colon on a step means its a terminal command)

Step – Backup via Time Machine (to be restored later)

Step – Create a macOS (Mojave) boot usb drive (9to5Mac Article)

Step – Boot off usb drive (hold option key) and secure erase the HDD.  Since the HDD will be left inside the iMac, best to be safe and securely erase it.

Step – Launch Terminal from top menu Utilities 

Step -: diskutil list (to determine the name of the synthesized fusion disk drive such as /dev/disk2)

Step -: diskutil secureErase 0 /dev/diskX (where diskX is the name of the disk to HDD) (This can take hours depending on your drive size) (this does a single pass of zeros written for security, there are options to do more)

Installing SSD Steps 

Based on https://www.ifixit.com/Guide/iMac+Intel+27-Inch+Retina+5K+Display+Hard+Drive+Replacement/30522

& https://www.ifixit.com/Guide/How+to+Add+An+SSD+To+The+27-Inch+iMac+(Late+2015)/67309

Step 1 – Lay iMac on its back 

Step 2 – use roller tool to cut thru glue

Step 3 – use plastic cards to separate remaining glue (takes time and work)

Plastic Cards

Step 4 – lift up screen ad prop up with boxes

Step 5 – unplug old HDD

Step 6 – plug in new SSD

Step 7 – attach adhesive strips to SSD and stick to iMac wall, as near HDD as possible.  Slight angle is needed for opposite corners of SSD to touch curved wall.  I only put adhesive strips on opposite corners of the SSD.

Step 8 – move prop up boxes to inside the iMac so you can do the next step

Step 9 – remove all adhesive that held screen in place (takes the most time)

Step 10 – use alcohol wipes to clean up where the strips go

Step 11 – apply new strips

Step 12 – lower screen back down to adhere to new adhesive strips

Step 13 – Boot up iMac and begin post install steps

Post Install Setup Steps (colons refer to terminal commands)

Step 14 – Boot off macOS usb drive by holding down Option

Step 15 – Launch Terminal from top menus

Step 16 -: diskutil list (to determine the names of the old internal SSD and new added SSD)

Step 17 -: diskutil coreStorage create fusion /dev/disk1s1 /dev/disk0s1 (where disk1s is the faster internal SSD and disk0s1 is the new SSD

Step 18 – a unique UUID will be displayed identifying the new volume group.  Copy this to clipboard.

Step 19 -: disktuil coreStorage createVolume UUID-FROM-PREV-STEP jhfs+ “Macintosh HD” 100% (This note is likely changing those quotes to evil quotes, you’ll want to type this up with non-evil quotes so a reader can copy them)

Step 20 – open disk utility

Step 21 – Erase the new Macintosh HD with the APFS option

Step 22 – Restore from Time Machine

Step 23 – Open Photos (does restoration for a long time)

Step 24 – Open Mail (does some migration)

2011 Mac Mini Hard Drive Upgrade Video

We just upgraded a 2011 Apple Mac Mini to have an SSD, a second hard drive, and new RAM.


Also available on YouTube in High Definition or Standard Definition.

Parts List

  • OCZ 120 GB Vertex 3 SATA III 6.0 Gb-s 2.5-Inch Solid State Drive VTX3-25SAT3-120G
  • Western Digital 1TB Blue WD10JPVT 5400RPM, 8 MB cache, 2.5 inch, 9.5MM height hard drive
  • Corsair 8 GB DDR3 Laptop Memory Kit CMSO8GX3M2A1333C9
  • Apple Mac Mini Model MC816LL/A 2.5 GHz Intel Core i5 dual-core processor, AMD Radeon HD 6630M graphics, 4GB RAM, 500GB hard drive
  • Cable: Apple Part 922-9560, also called “Apple Mac Mini Server (Mid 2010) Bottom Hard Drive Server Flex Cable” or “Hard Drive Flex Cable Bottom”. We used part number 1009005 at welovemacs.com. This is sold as a kit from ifixit.com.

Alternate Parts List

The OCZ Vertex 3 is the fastest consumer SSD at the moment. Other SSD’s that you might consider include:

The Western Digital Blue drive mentioned above is high capacity and quiet. For a faster spinning hard drive consider:

The dedicated graphics in the mid-tier Mac Mini make it worth it for me. But for the cheapest Mini, consider:

  • Apple Mac Mini MC815LL/A 2.3 GHz Intel Core i5 dual-core processor, integrated Intel HD Graphics 3000, 2GB RAM, 500GB hard drive

UPDATE: My video shows adding two 9.5MM height drives. I just upgraded another Mac Mini with a 9.5MM SSD and a 12.5MM standard hard drive. As with my first upgrade, the hard drive goes in the bottom slot (the side closest to the top of the case when upright). This does fit. But first you need to slide the logic board out slightly. Be sure to remove the IR port adapter before sliding out the logic board. The OWC video shows how to do this. I used a cut up coat hanger to insert into the logic board holes and slide it out.

First Boot

Starting with a blank hard drive is easy on the 2011 Mac Mini. Hold down Command-R to boot into Lion Recovery which allows you to format the drives and download Lion over the Internet.

TRIM Support in Lion

For optimal SSD performance, enable TRIM support within OS X Lion. Grant Pannell describes the terminal commands to enable TRIM.

Photos of Upgrade

Fan Removal
Fan Removal
WiFi Connection
WiFi Connection
Empty Hard Drive Bay
Empty Drive Bay
Original Hard Drive
Original Hard Drive
Drive Bay Side View 1
Drive Bay Side View 1
Drive Bay Side View 2
Drive Bay Side View 2
New Hard Drive & Cable
New Hard Drive & Cable
New Hard Drive Insertion
New Hard Drive Insertion
New SSD & Drive Cables Attached
New SSD & Drive Cables Attached
Attach Fan
Attach Fan

Aluminum iMac Hard Drive Upgrade

What you need

1. T6 and T8 torx screwdrivers
2. Phillips Head screwdriver
3. Microfiber cleaning cloth
4. Suction cups
5. External USB or firewire backup hard drive
6. New SATA hard drive. We recommend the 1.5TB Western Digital Green Drive

Step 1 – Backup via Time Machine

Before you start, you have to first make sure you have a recent time machine backup.  After installing the new drive, we will restore from this backup.

imac ram slot

Step 2 – Remove RAM slot

The RAM slot is held on with just 1 screw.  Unscrew it and pop off the panel.  The screw does not fall out but remains in the panel itself.  If you are upgrading RAM, this all all you need to do.


Step 3 – Remove the glass screen

This may seem like a scary step but it is extremely easy.  Firmly attach suction cups at opposite corners.  Then gently lift up.  The glass is held on with magnets and comes off with very little effort.  I recommend laying out a towel or paper towels to lay the glass on.  Be careful not to scratch the glass or screen beneath it.  If at all possible, try to do this work in a non dusty area because we will later need to clean off the dust between the glass and LCD screen.

imac-hdd-03Step 4 – Remove front aluminum casing

There are 12 screws around the edges holding on the front aluminum casing.  Unscrew them all keeping track of which ones go where since they are varying lengths.  You can then lift upwards around the edges to take off the front casing.  Flip it towards the top of the imac and lay it on the table above it so that you do not have to unhook the camera.

imac-hdd-04Step 5 – Remove LCD panel

The LCD is held down with 8 screws on the sides which need to be removed.  There is a cable marked in green toward the bottom which needs to be unhooked.  There is also a connector to the right marked in yellow that is held down with 2 screws.  Remove the screws and pull the connector upwards to unhook it.  You should then lift up the LCD gently where you will see 2 power connectors toward the upper right that need unplugging.  The LCD should then be free to place elsewhere.  The hard drive will now be visible.

imac-hdd-05Step 6 – Remove the old hard drive

There is a cushion glued on top of the heat sensor cable.  Gently pull up this cushion keeping it in one piece and try to maintain its stickiness for later.  The heat sensor is held in place in a plastic notch and can slide out of it.


imac-hdd-07There is a black plastic bar holding the hard drive in place.  Lift it up from left to right to unlock it.  This can be very challenging since it is tight.  The drive can then slide up and out and you can unhook the power and SATA cables.


Step 7 – Add the new hard drive

There are 4 screws on the old hard drive which need to be removed and added to the new hard drive so that it can slide into the holders on the iMac.  Once the power and SATA cables are plugged back in, you can slide it back in and lower the black plastic bar to lock it in place.  Place the heat sensor on the drive in about the same area where it was and use the sticky cushion to hold it in place.  If it doesn’t seem sticky enough to hold, you can get some rubber cement from your local home depot and add just a bit to hold it in place.

Step 8 – Put the system back together

Rebuilding the system is mostly straightforward.  It can be handy to have an extra pair of hands to hold the LCD as you reconnect the power cables.  We recommend you lay out the screws in an orderly manner so that you know exactly which one goes where as you rebuild.

Once the system is rebuilt except for the glass, you want to use the microfiber cloth to remove any dust or debris on the front of the LCD screen and back of the glass.  You will also need to use the microfiber cloth to clean the front of the glass once you remove the suction cups.

imac-hdd-10Step 9 – Restore from Time Machine backup

When you first boot up, insert the Mac OS X install disc and hold down the option key while booting so you can select the disc to boot from.

Step through the install until the Utilities menu appears at the top of the screen.  First use Disk Utility to erase the disk and create a volume.  Then choose to restore from backup from the same menu and choose your external time machine backup.  Your system will then be just as it was except with a new hard drive.