NVMe enclosure compatability: drive won’t fit


I have an NVMe drive and an M.2 enclosure. However my drive doesn't easily slot into the enclosure connector like I expected, so I'm wondering if I've bought the wrong enclosure type, or the enclosure is faulty somehow.

Here is a picture of both side by side:

enter image description here

Are these two compatible?

thanks in advance!

Best Answer

Not all M.2 drives are NVMe – cheaper ones are SATA – and the two use different connections – some of the pins on your M.2 connector are for PCI-Express (i.e. NVMe) and some are used for SATA.

M.2 slots on PC mainboards have both connections routed to somewhere since they have both PCI-Express and a SATA controller anyway, but most enclosures only have one or the other.

(Making a SATA-only M.2 enclosure is as cheap as making a generic SATA enclosure, but NVMe (PCI-Express) requires a more complex controller chip; and if the manufacturer tried to do both, then they'd probably have to throw in a USB-hub chip as well, making it a bit more expensive.)

In short, you need to get an M.2 NVMe enclosure.

It appears they're supposed to be physically compatible though, and these two don't appear to be

Many NVMe SSDs do not have the 'B key' notch (are M-key only) so that they could use two additional PCI-Express lanes – which are on pins 12-19, exactly the position that the B-key would cut out.

(But being "physically compatible" would be useless, since the SATA host controller in your enclosure couldn't talk to an NVMe (PCI-Express) device anyway.)

Related Question