Chosen Solution
After a dive through the ifixit tear-downs, I now know that my iMac (21.5in late 2013 emc2638) currently has an unpopulated (12+16 or 8+18 pin?) pcie slot for the fusion drive. I am planning to upgrade this and some other parts, but don’t want to bother with the pcie slot if the only available parts are the recovered/refurbished apple ones. OWC sells these: https://eshop.macsales.com/item/OWC/SSDI… and these: https://eshop.macsales.com/shop/ssd/owc/… Neither of these parts is advertised as being compatible, but I have heard elsewhere that my iMac shares the ssd interface of at least one of these other macs. Is this upgrade possible with 3rd party components/adapters?
The 2013 machines were odd ducks in both the iMacs and the MBP as to the storage card. Also on the Envoy case. OWC is not showing a PCIe card for your model. Here are the comparable options they are showing: https://eshop.macsales.com/upgrades/imac…
Unfortunately i will have to disagree with mayer… Not having torn your model of iMac down personally I will have to defer certain knowledge to others. If you look through this piece on everymac.com it states that the Late 2013 iMac does have a slot for a PCIe SSD whether or not the system was configured with a Fusion Drive from Apple. https://everymac.com/systems/apple/imac/… ‘Remember this is NOT a PCIe slot that will take M.2 drive. It is a propriety slot that very few manufacture drives to this specification. So that said, you may find that your best option is OWC (they are good people, call them they will know what your options are and the best way to fill them). Lastly… you could simply replace your hard drive with a SSD and be done with it (your standard drive is a 5400 RPM drive rather than the faster 7200 RPM drives - ALWAYS use high quality SSDs, not the “cheepest” ones that are on sale at your local computer accessory store). This might be your best and easiest option. And if you have a friend with a 2008-2012 Mac Pro you could easily clone your drive so you don’t have to reload everything (although if you are able and have the patience this is a very good option). Good luck on your upgrade!
