Replacing Drives on 2013 late model imac

faaslave wrote:

Thanks for the reply. I would rather replace the internal drives. I am comfortable doing that. The issue I have is 1) knowing what drives to get to replace them

OWC is your best option since you will need the adhesive kit to reattach the display & the tool to separate the adhesive for removing the Display Assembly. Make sure to keep the Display vertical at all times or you risk having it crack under its own weight.

2) is it really two drives in there. As you can see form the screen shots I posted, it is unclear to me

Yes, you have a Fusion Drive setup.

I would only recommend replacing the 2.5" hard drive and leave the original Apple SSD alone since you must remove the Logic Board to access the OEM Apple SSD IIRC. This is a very risky since everything pretty much needs to be removed in order to remove the Logic Board. It is not always easy to reinsert the Logic Board.

You can check out the installation videos on the OWC website, but keep in mind the videos make it look easier than it really is. Even an experienced tech can find it a bit daunting & difficult. Just want to give you the warning so you are prepared for it.

OT is correct, it would be MUCH MUCH wiser to use an external SSD. This is far easier and much less likely to goof up the computer. It is also less expensive too. Note that your computer is technically obsolete and now is 11 years old so that means internals are brittle and easy to break. Because it's obsolete, if you open it and accidentally break a cable or connection you just ruined the computer as a replacement parts will not be available. In addition, the computer will not run current versions of Mac OS (even upgraded it won't) so that is also something you may want to consider.

Installing an external SSD is simple, just follow the instructions in How to setup an external SSD as your startup disk and I'd recommend contacting OWC (www.macsales.com) to assist selecting the best external (or internal) SSD option for your vintage machine.

Which ever decision you make, best of luck!

I would recommend just using an external USB-3 to M.2 NVMe enclosure. Those are just as fast as an internal Sata SSD, will save you the labor of opening up the iMac, and can be easily reused as an external drive on a newer Mac whenever you upgrade.

Otherwise 27" 2013 iMacs sold with fusion drives have:

> a 3.5" SATA HDD in front which can be replaced with either a SATA SSD in a 2.5" to 3.5" adapter or another high capacity 3.5" HDD.

> a proprietary blade SSD on the back of the logic board. Other World Computing (aka: macsales.com) sells custom SSD blades that fit Apple's connector.

I think you'd be best served to get an external SSD of the appropriate size (1 or 2 TB), clone your current drive to it with Carbon Copy Cloner and boot and run from the SSD. This way you could use the SSD with another Mac when the 2013 gives up the ghost. You would avoid the danger of opening up the iMac for replacing the fusion drive or the cost of having a tech do it. You could also erase the internal drive(s) and use them for data storage.

The most economical way to go would be with a USB to SATA adaptor and a bare SSD like this:

I have several of them for external data drives and to boot from older systems to use older software.

The adaptor also lets you change out drives quickly and easily when used for data storage.

If you would prefer an SSD in its own enclosure I recommend you contact Customer Support at OWC (MacSales.com) for their recommendation of which of their devices would be best for your particular iMac model, workflow and budget. OWC is considered the premier 3rd party hardware supplier for Macs by most of the experienced users here.

I'm with the other responders who recommended against replacing the SSD. It's a blade SSD and Apple appears to have used both SATA and NVME blades in various iMacs. You probably won't know which you have until you tear the entire iMac apart. (And even after removing the logic board, pulling the blade SSD itself is an extra delicate operation.)

Also, macOS is not "loaded on the SSD" with everything else on the HDD as you wrote above. While some portion(s) of macOS may be installed on the SSD, the SSD serves primarily as cache for the HDD. The point being that the 2 parts of the Fusion drive operate inseparably as one.

Also the reference to MSDOS FAT-32 is for the EFI partition on the drives. It's a necessary component and is separate from what you may think of as the "normal" HFS+ partition or APFS container.

I would echo Old Toad's advice about contacting OWC to search for internal drives for your Mac. and they also have DIY instructions on their site so you can see what that operation involves.

Then I'd contact OWC and see what they recommend as an SSD replacement.