Where's the "Fast Flash" ?

[Sponge Bob]

Dear all,

I have a 2012 21.5 inch iMac, EMC 2544, 3.1 GHz Intel Core i7, with a Fusion Drive containing 1 TB HDD + 128 Gb of fast flash/flash RAM.

My question is, where are the Fast Flash chips actually located ?

Reason I'm asking, I want to replace the logic board and I'd like to know if they are on the Logic Board. I see replacement logic boards for sale but no mention of the fast flash.

Excuse my ignorance, I really have trawled the net for the answer to this.

thanks

 

[Raz0rEdge]

In the space of storage, there is HDD, SSD and Hybrid. HDD are traditional spinning media, SSD is all flash storage. Hybrid is what drive manufacturer's call a drive which is a HDD with a small amount flash added to it. Fusion drive is Apple's implementation of the hybrid drive likely using a regular HDD and adding some flash on the logicboard to present as a single storage device. The advantage of Fusion over Hybrid is that macOS does some extra work to keep things in the flash portion when actively/constantly being used where Hybrid uses the flash purely for caching purposes.

Looking at the teardown of the 21.5" iMac on iFixit, you can see the 64MB serial flash memory in this configuration. That value might change based on your iMac config, but likely is still sitting on the logicboard. Apple is likely not using Hybrid drives along with their Fusion technology since that would just cause greats amounts of confusion.

 

[harryb2448]

You can replace/have replacedf the PCI-e storgae in your iMac but it is task for a very experienced folk only. The LCD is glued in and cracking them can be a real problem. Here is a 'how to from OWC and also details of the Aura 6Gb/ps PCI-e drives:-


https://www.youtube.com/watch?v=FeyXd-lcojo&feature=youtu.be


https://eshop.macsales.com/item/OWC/SSDIM12D240/

 

[Sponge Bob]

Here it is.
Samsung part number MZDPC512HAG1 ( 128 GB - SSD, non-spinning part of the Fusion Drive )

 

[MacInWin]

Just a caution on Fusion drives. The way they work makes both the spinner and the memory modules critical to operation. Lose either and you lose both. I would very strongly suggest that before you start mucking about with the logic board that you make a full, complete and tested backup of the fusion drive to an external drive. That way, if/when you break the link between the spinner and the modules, you will be able to restore what you broke.