As people already know they are physically compatible, you can plug an M.2 SATA (aka M+B key) into an M.2 NVMe (M key).

My question is will it work?


  • 1
    What motherboard are you using? Mar 14, 2018 at 9:42
  • 1
    According to wikipedia M keyed means "PCIe ×4, SATA and SMBus". So a M-keyed M.2 port can do both PCIe/NVMe and SATA.
    – Hennes
    Mar 14, 2018 at 14:24
  • @Hennes Interesting, so that would mean yes... In theory an M.2 NVMe equipped Macbook Retina could accommodate an M.2 SATA drive.
    – unom
    Mar 14, 2018 at 17:14

5 Answers 5


A slot that can do SATA will have the M key and/or B key.

A slot that cannot do SATA will not have either the M or B key, but others instead, making it physically impossible to insert a SATA-only card.

A card with multiple keys can only use the lowest common set of features. With B+M, that’s PCIe x2, SATA and SMBus.

Because an M.2 NVMe SSD typically wants PCIe x4, there’s only one possibility: M key.

It might be noteworthy that slots with multiple keys are very rare, if they exist at all.

If a card physically fits the slot, it will work. That’s the entire idea behind the key notches.

  • 1
    Corrected the type I meant M+B key versus just M key. this is the case I described. In this case one can insert a M+B key drive into a just M slot it fits. The other, connecting a M key drive to an M+B key slot is impossible.
    – unom
    Mar 14, 2018 at 12:54
  • @unmircea I updated my answer. Please accept an answer if it answers your question. If you need further clarification, please let me know.
    – Daniel B
    Mar 15, 2018 at 11:19
  • In Asus laptop, Q534UXK is possible to connect SATA m.2 or PCI m.2. but the motherboard has a label with the two options!
    – RckLN
    Sep 11, 2018 at 3:20
  • 1
    @Daniel B, i'm sorry, I still confused. Motherboard that has M.2 Slot with M key not always support SATA Card M+B, just like a case from here forums.lenovo.com/t5/…
    – ariefcfa
    Oct 5, 2020 at 9:56
  • 2
    This is very wrong, you have M key slots that don't support SATA, in fact it's very common now.
    – Oleg
    Oct 21, 2020 at 0:27

Just because an M only slot fits into M+B slot does not necessarily mean it will work.

Here is an example : M-Slots for M+B and M only


NVME drive uses pci-e signal, while SATA m.2 still uses SATA signal. They are quite different. Most ssd enclosures only support either one protocol, while most motherboard m.2 ports usually support both standards at same time. (There are some exceptions.) If your port is m.2 b+m, then you can only use sata m.2 ssd. If your port is m.2 key m, you should be able to use nvme ssd, and you *might* be able to use sata m.2 ssd.


Support for NVME is largely determined by the BIOS. For a motherboard with a m.2 slot, it can work with m.2 SATA SSDs that usually have the B and M cut-outs and the slot normally has only the M key on the right side. A m.2 NVME SSD will slot in but usually won't work unless the BIOS has an option to set the m.2 slot to either SATA or NVME. If a motherboard has a m.2 slot and was made before 2016 it's unlikely to support NVME, but check your motherboard manufacturers' website for a BIOS update that may add support for NVME.


I just bought a new replacement SSD on recommendation from a PC retailer who offered the correct option for my laptop without me knowing anything about what Slot was in my laptop. I received a new NVMe m slot SSD HD but when I opened my laptop was alarmed to find it fitted with a SSD HD with an M+B slot in it.
I scratched my head a little, took out the M+B Sata Drive and the NVMe M only slot drive straight into the existing port. flipped it over and expected nothing but Bios errors. To My suprise the NVMe M slot Drive worked perfectly. hope my experience helps someone

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