Stefan Mileschin

Apple was an early adopter of PCIe SSDs, introducing them in 2013 when the NVMe specification was still in its infancy and before any M.2 NVMe hardware was available. As a result, Apple's PCIe SSDs for the era used a proprietary form factor rather than the now-common M.2 standard. But form factor limitations aside, they were still physically and electrically stand-alone SSDs, meaning that unlike Apple's latest machines with integrated SSD controllers, these machines could have their SSDs swapped out for an upgrade.

This is where Mac accessory and upgrade specialist Other World Computing (OWC) comes in. OWC has offered several aftermarket SSDs in Apple's custom not-quite-M.2 form factor, culminating in the recent release of the Aura Pro X2 SSD. Designed to be a drop-in upgrade, this is a modern high-end SSD with 3D TLC NAND and the latest Silicon Motion SM2262EN controller, with the reference M.2 PCB layout adjusted to fit Apple's form factor. So for older Mac users – and particularly Retina-generation MacBook Pro owners – the Aura Pro X2 SSD presents a chance to breathe some more life into these machines with a newer, larger SSD.

https://www.anandtech.com/show/14382...for-older-macs