Thanks for your answer Scott,
I hope you can help me a little bit more
How can I tell if my card has M Key, except that I can see that it has both notches on the connector?
I wanted to install on Supermicro Motherboard C9-X299PGF, but Supermicro says that this is motherboard supports only high speed NVMw SSD's, and should not support SATA M.2.
They seem to be a little insecure with the answer, since this is their new and latest motherboard.
This is what the specifications of the motherboard says.
Specs are saying that this M.2 interface is PCI-E 3.0 x4. Does that mean that because of that it will not support SATA cards and is not using the SATA bus??
Here is also the block diagram from this MBD:
So I am confused it this Motherboards should really support this M.2 SATA DC-S3520 card or not.
I am not seeing it in BIOS, tried to UEFI installation of windows and again card is not recognized or detected.
Do you have any advice?
M.2 Keys are linked to specific applications.
*From Wikipedia's page on M.2
B and M are for storage (PCIe, SATA, USB, etc):
Other keys (like as A and E) are used for other types of products, such as wireless adapters:
The best thing to do is to always make sure that your motherboard manufacturer lists the M.2 slot under their "storage" category. You will then need to see if it meets the requirements for your SSD, in this case, you will need to make sure that your M.2 slot supports SATA 3.0 (6Gb/S). If the M.2 slot is listed only under "expansion slots" for example, it may not be intended for storage.
Carlos has provided all the technical information. I will summarize. Notches will be in specific places to indicate the connectors keying. On most devices, the Type that the slot refers to is usually printed on the card itself. That is, on the side of the card that components are attached to, right by each slot, you should see a little 'M' or 'B' (or, for wireless cards, a little 'A' or 'E'). It there are two slots, there should be letters for each.
Now, in a compliant Type M slot, the x4 PCIe lanes as well as a SATA lane are supposed to be present. The card will indicate (via signal on one of the pins) to the motherboard whether it is going to use the PCIe lanes or the SATA lane (my understanding is that both cannot be used by a card; it's one or the other).
It is certainly possible that the boobs at Supermicro implemented a non-standard M.2 socket that will only support M.2 NVMe drives (i.e. will not support M.2 SATA drives). This would be a specification compliancy violation, IMHO.