Talk:M.2

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To-do list

What is the relation between "gum stick" SSDs used in, for example, MacBook Air — and the NGFF / M.2 SATA SSDs? Dsimic (talk) 14:26, 14 September 2013 (UTC)[reply]
"Gum stick" SSDs are proprietary (not standardized like M.2) — Preceding unsigned comment added by 192.55.55.39 (talk) 17:25, 14 July 2015 (UTC)[reply]
What kind of interface do they use, both bus-wise and at the logical level? — Dsimic (talk | contribs) 20:51, 14 July 2015 (UTC)[reply]
Some images should be provided for an illustration of different M.2 sizes, and/or for a mSATA vs. M.2 comparison. -- Dsimic (talk) 01:45, 18 September 2013 (UTC)[reply]

Are M.2 and M.3 compatible?

te Could you please add to the article if one could use an M.2 in an M.3 slot and vice versa?--82.37.174.248 (talk) 00:38, 31 December 2018 (UTC)[reply]

M.2 is being updated with PCIE gen 4 inside of it. This maintains compatibilility

m.3 is an awkward terminology, it was a proposed terminology for the update from PCIe gen 2 to PCIe gen 3, but they haven't bothered. This may be because the CPU may provide PCIE gen 4 and the chipset a lesser PCIe, and also that these are backward compatible in both directions... gen x device to gen y socket, for all x and y, for both PCIe and SATA. They both then talk at the slowest speed. See PCIe and SATA

So they really want to focus on the form factor and connector being M.2 (mechanically) , and the PCIe/sata version is whatever is lesser of what is connected together.

27.96.199.11 (talk) 11:00, 2 September 2020 (UTC)[reply]

According to Anandtech, PCI-SIG was unhappy with Samsung calling it M.3 (since it is incompatible with M.2)^[1] and issued a warning to the industry and consumers.^[2]

I'm not sure this dispute between PCI-SIG and Samsung is worth a small note on the article, but I'd guess not (at the same time, I think it'd be ok to quickly mention it). Feelthhis (talk) 12:10, 6 December 2020 (UTC)[reply]

References

^ Anandtech
^ "M.2 Interoperability Warning" (PDF). Archived (PDF) from the original on 6 December 2020.

M.2 keying table

The existing table is somewhat helpful but not intuitive, and is basically a copy of a table in figure 3 of the spec.^[1]^: 23 I propose a somewhat more complex table that is far more descriptive.

M.2 Module Keying^[1]^: §3
Key ID	Notched Pins	Primary Interface	Additional Interface Choices	Intended Use^[1]^: §5
M	59–66	PCIe (4 lanes)	SMBus^[2]	Solid-state drives
M	59–66	SATA
B + M	12–19, 59–66	PCIe (2 lanes)
B + M	12–19, 59–66	SATA
B	12–19	SATA
		PCIe (2 lanes)
		PCIe (2 lanes), USB 2.0, UIM^{[note 1]}	2^nd UIM	Wireless WAN or other (especially future) applications
			Audio, GNSS (I²C)
			Audio, HSIC (USB 2.0), IPC
		USB 3.0 or SSIC, USB 2.0, UIM	2^nd UIM
			Audio, GNSS (I²C)
			Audio, HSIC, IPC
A	8–15	2x PCIe^{[note 2]}, USB 2.0	DisplayPort, I²C	Connectivity such as Wi-Fi, Bluetooth, NFC, WiGig, especially for wireless DisplayPort
A + E	8–15, 24–31	2x PCIe^{[note 2]}, USB 2.0	I²C	WiFi, BT, NFC, or other connectivity
E	24–31	2x PCIe^{[note 2]}, SDIO, USB 2.0	I²C, UART, PCM (I²S)	WiFi, BT, NFC, or other connectivity

^ The specification refers to a 'User Identity Module', whose purpose and operation are application dependant. It does however mandate compatibility with ISO/IEC 7816. Thus colloquial SIM cards are compatible, and some of the documentation refers to SIM explicitly.
^ ^a ^b ^c 2 separate PCIe interfaces, with 1 lane each. Optionally, can be combined into 1 PCIe interface with 2 lanes.

I'll wait for a week or so before changing the article. Vickas54 (talk) 04:28, 31 May 2021 (UTC)[reply]

I completely agree. Besides, the whole article is focused on storage, while M.2 is also used for other purposes. There is a good article, discussing all types of M.2 cards here: https://www.dell.com/support/kbdoc/en-us/000144170/how-to-distinguish-the-differences-between-m-2-cards 213.134.65.133 (talk) 10:38, 2 June 2021 (UTC)[reply]

References

^ ^a ^b ^c "PCI Express M.2 Specification, Revision 1.0" (PDF). PCI-SIG. November 1, 2013. Archived from the original (PDF) on June 13, 2020.
^ "SMBus interface for SSD Socket 2 and Socket 3 (PCI-SIG engineering change notice)" (PDF). PCI-SIG. August 11, 2014. Archived from the original (PDF) on July 14, 2015. Retrieved August 5, 2015.

Screws to secure M.2 cards

I came here looking for information on the screw needed to secure an M.2 card. They are hard to find. Are they metric M3 threaded screws? Is there a standard size? What does the standard require? 174.28.55.191 (talk) 15:30, 5 July 2021 (UTC)[reply]

[1] Anandtech

[2] "M.2 Interoperability Warning" (PDF). Archived (PDF) from the original on 6 December 2020.

[UIM-5] The specification refers to a 'User Identity Module', whose purpose and operation are application dependant. It does however mandate compatibility with ISO/IEC 7816. Thus colloquial SIM cards are compatible, and some of the documentation refers to SIM explicitly.

[combine_PCIe-6] 2 separate PCIe interfaces, with 1 lane each. Optionally, can be combined into 1 PCIe interface with 2 lanes.

[pcisig_2013-11-3] "PCI Express M.2 Specification, Revision 1.0" (PDF). PCI-SIG. November 1, 2013. Archived from the original (PDF) on June 13, 2020.

[M.2_SMBus-4] "SMBus interface for SSD Socket 2 and Socket 3 (PCI-SIG engineering change notice)" (PDF). PCI-SIG. August 11, 2014. Archived from the original (PDF) on July 14, 2015. Retrieved August 5, 2015.

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