Help with M.2 SSD keying

Ceph92

Limp Gawd
Joined
Sep 17, 2019
Messages
132
Hi - I'm new to m.2 drives, and want to make sure I'm getting the keying right. Do some sockets mount the SSD card upside-down, where the label faces down? Is this adapter an m-key socket? Note the side the key is on, and both msata + ngff in the description.

https://www.newegg.com/p/0BD-00KP-0...f &cm_re=sata_ngff-_-9SIAFS976S6976-_-Product

The reason I'm looking at this is that I have a laptop with an m.2 NGFF ssd, which I want to upgrade. However, I can mount the old m.2 card in the SATA 2.5" bay as this guy did:

https://www.dell.com/community/Prec...cision-3510-2nd-hard-drive-part2/td-p/7305362

Thanks for any hlep.
 
No, M.2 will ALWAYS be controller chip up. The keys are dependent on how many lanes it uses, and could be whether it uses PCIe or SATA. PCIe will be the faster of the 2, and that would be fastest with an M key. I see more m.2 SATA drives with a B+M key these days, so chances are, if it has both keys, it's probably SATA. M keys will likely be PCIe, but check the product description to be sure.
?u=https%3A%2F%2Fmagixxl.com%2Fwp-content%2Fuploads%2F2018%2F04%2F51xgXt1cWdL.jpg


The picture you gave shows a B Key, you will have to check whether you are using a SATA m.2, but regardless, only B Key or B+M key drive would work on that adapter, and it won't work at all with a PCIe drive, only SATA M.2
 

Attachments

  • ?u=http%3A%2F%2Fwww.delock.de%2Finfothek%2FM.2%2Fimages%2Fkeys-b-m_klein_engl.jpg
    ?u=http%3A%2F%2Fwww.delock.de%2Finfothek%2FM.2%2Fimages%2Fkeys-b-m_klein_engl.jpg
    42.8 KB · Views: 24
Last edited:
Maybe this will show what he has going on in his system... 2 completely different type of drives.

upload_2019-9-17_11-38-44.png
 
No, M.2 will ALWAYS be controller chip up. The keys are dependent on how many lanes it uses, and could be whether it uses PCIe or SATA. PCIe will be the faster of the 2, and that would be fastest with an M key. I see more m.2 SATA drives with a B+M key these days, so chances are, if it has both keys, it's probably SATA. M keys will likely be PCIe, but check the product description to be sure. View attachment 187812

The picture you gave shows a B Key, you will have to check whether you are using a SATA m.2, but regardless, only B Key or B+M key drive would work on that adapter, and it won't work at all with a PCIe drive, only SATA M.2

Looks like my existing SSD is B+M, though the socket supports M. I assume that means the adapter would work for that SSD. And it makes sense that the adapter would have only a B key, because it's just for SATA. What I don't know is whether the B-only key means mSATA or m.2 B-key or whether those are the same thing.
 
Thanks for the illustration, Nside. It helps in being very clear about what we're talking about.

Another question: what is NGFF? Is that just the form factor? I was guessing that NGFF was strictly about m.2 M-key. THough that makes the product description a bit confusing.
 
NGFF is just another term for M.2 as far as I know... New Generation Form Factor or something... likely only seen on older m.2 stuff...
 
PCIe will be the faster of the 2, and that would be fastest with an M key. I see more m.2 SATA drives with a B+M key these days, so chances are, if it has both keys, it's probably SATA. M keys will likely be PCIe, but check the product description to be sure.

Rethinking this.... all that is very confusing. Is my understanding correct?

  1. M-key only is PCIe only -- and not guaranteed to be 4x
  2. B-key only is SATA only
  3. M+B key cards are either PCIe or SATA
  4. M+B key sockets can support both PCIe and SATA
  5. PCIe SSDs are amore general classification that include M.2 M-key 4x
Can some m.2 cards support both PCIe and SATA?

*edited for clarity
 
I tend to stay away from absolutes, mainly because many companies do really dumb stuff.

BASIC rule of thumb is

Drives:

M key = PCIe

B+M key = SATA

Sockets:

M Key = PCIe, also probably supports SATA, but will disable some SATA port(s) elsewhere. Sometimes doesn't support storage at all, only network adapters and such.

B Key = Older Standard, Check the Owner's Manual, but most likely SATA. Sometimes doesn't support storage at all, only network adapters and such.

The sockets get wonkier with compatibility/keys than the drives tend to, so check any manual you can find for the motherboard... and make sure you know for sure which type of drive you are buying, how it's keyed, length, etc...

Edited for more info
 
Last edited:
I tend to stay away from absolutes, mainly because many companies do really dumb stuff.

Ugh, ok.

Thanks a lot for your help. This made my planning a bit easier (and I can plan around your caveat above).
 
See, Here's some weird stacked M Key M.2 sockets on a mini-ITX embedded APU board I have.
They won't work for PCIe or SATA drives, and are meant for network adapters, which I have in the bottom socket.
They will, however, work with a SATA adapter card.
upload_2019-9-17_12-58-26.png
 
See, Here's some weird stacked M Key M.2 sockets on a mini-ITX embedded APU board I have.
They won't work for PCIe or SATA drives, and are meant for network adapters, which I have in the bottom socket.
They will, however, work with a SATA adapter card.
View attachment 187837

That's pretty interesting. But that SATA board includes a PCIe-SATA bridge? I've seen a lot of devices for sale like that but it's always unclear if they will work on the mainboard (of whatever). My laptops have whitelists for pcie devices, though it may be to protect against creative/crazy manufacturers.

What do you use APUs for? I haven't seen those in a while, except for bitcoin.

I have had this fantasy of an programmable ARM-based mini-PCIe processor card to supplement older computers.
 
Last edited:
Btw is tha really a B-key? There seem to be more key types than just M+B. Compare m.2 B key (4 pins separated) with mSATA B key / what you show above (8 pins separated).
 
I looked at it again, and you're right. Been a couple years since I built this little thing.

This is Mini-PCIe or something like that. Just goes to show how screwed up things can get without looking in to them though.

I bought this board on clearance, as i wanted to see if I could make an X86 answer to Raspberry Pi, only larger... It was on clearance for $17, and I couldn't help myself... Long story short, it works fine for a no-frills NAS controller, not much else.

BTW, it's closer to an M key than a B key... but it's in-fact neither. Good eye

Btw is tha really a B-key? There seem to be more key types than just M+B. Compare m.2 B key (4 pins separated) with mSATA B key / what you show above (8 pins separated).
 
Yeah, here's a Mini-PCIe SSD that is also MSATA. Not trying to confuse things, but just goes to show how many weird standards there are or have been surrounding these little PCIe slots.

upload_2019-9-17_13-59-1.png


M.2 has standardized them more I think, but I still take nothing for granted. Especially embedded or proprietary boards like laptops or even desktops from companies like Dell. If they can have their board makers use existing sockets, but only allow certain HW to use those sockets, they will because it's cheaper. That's why I say, read the manual, and look online to see what someone else has got working.

Buying a name-brand motherboard off the shelf is usually safe though.
 
Back
Top