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A1418 / EMC 2833 / Late 2015 / 3.1 GHz Core i5 or 3.3GHz Core i7 Processor. Released October 13, 2015.

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Where is the SSD Controller inside the late 2015 21.5 iMac

Had someone replace the Fusion Drive in my iMac (late 2015) with a 1 TB SSD. I am using it now to send this but it seems that the SSD Controller for the Fusion Drive was missed during the operation since it still shows up in Disk Utility as well as Drive DX as part of the system. Just wondered where the “ SSD Controller for the Fusion Drive” is so the next time I have the iMac open it can be removed.

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You are in fact seeing the second drive your system had. A Fusion Drive is made up of two drives a high speed but small SSD and a slower but deeper storage HD. It’s not one physical drive but two! Your friend replaced the HDD part with a SSD, but left the blade SSD still in your system which you can see here

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Here’s the needed guide to get to it: iMac Intel 21.5" Retina 4K Display Blade SSD Replacement. It’s a fair amount of work so I would leave it be. Its not very large and unless you got the larger 128 GB drive I would not use it as a boot drive as its just too small. Just reformat it to FAT32 and leave it alone.

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I thought Fusion drives were a SSD controller and flash chip(s) slapped onto the back of a hard drive controller board. I'll be darned.


You're thinking of a hybrid drive (SSHD) like a Seagate FireCuda at one point Western Digital offered a real dual drive WD Black2 it didn't last, within a year it was discontinued.


Thanks for your answer.


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