M2 SSD?

[xwrench3]

so, i am fairly new to the tech scene. and i want to be sure about something before discussing it with my son, who is way more advanced in this area than i am. am i understanding it correctly that an M2 ssd is quite a bit faster than a 2.5" ssd? i have also noticed there seems to be a couple of sizes (physically) of M2 drives. is there a reason for this like one is for laptops and the other is for desktops?   also, what other cards are there that fit into an M2 slot? thanks.

[paddy-stone]

No, the physical differences do not mean they are faster/slower. Some M.2 drives are faster because they are NVME drives, but NVME drives can also come in PCI card types and I believe 2.5" drives also... they are very new technology, so you'd have to check on your motherboard to see if it can handle m.2 type.. whereas pci type can go in almost any motherboard that had a 4x pci-e slot spare I think.

[Mecami]

I think this article should answer a lot of questions: http://www.computershopper.com/feature/2016-guide-the-best-m.2-solid-state-drives-tested

[Samfisher]

1 minute ago, paddy-stone said:

No, the physical differences do not mean they are faster/slower. Some M.2 drives are faster because they are NVME drives, but NVME drives can also come in PCI card types and I believe 2.5" drives also... they are very new technology, so you'd have to check on your motherboard to see if it can handle m.2 type.. whereas pci type can go in almost any motherboard that had a 4x pci-e slot spare I think.

NVME is only a controller specification, not a label for speed.  M.2 is a socket only, and it can either support SATA or PCIE drives.  And those can either be AHCI or NVME.

[paddy-stone]

Sorry, you must have kis-understood my response... I meant that in general NVME is faster, and can come in different shapes, same as normal AHCI. I apologise for the mistake OP if you didn't understand what I was trying to say.

[EmeraldFlame]

Well it depends on the underlying technology. Some M.2 SSDs will be faster, others will be more or less the same as 2.5" SSDs.

Some M.2 SSDs are actually still SATA based so with that they are limited to the 6Gbps/550MBps speeds we are used to seeing in 2.5" drives.
However other M.2 SSDs do actually use a PCIe x4 based interface natively which has considerably more bandwidth close to 32Gbps. We haven't seen anything really maxing this out yet, but theoretically we will probably see things hit around 3-3.5GBps give or take a little bit depending on overhead.

Furthermore there are 2 standards for handling operations within the drive, AHCI and NVMe. AHCI is an older protocol made primarily for hard drives while NVMe is a newer standard which handles queuing of requests better for SSDs. You will typically see higher speeds, lower latency, and lower overhead with NVMe.

As for the size, there really isn't a defined "this is for laptops, this is for desktops". The second longest variant has seemed to be settling around the standard for everything. But some smaller drives just don't need the physical space. No reason to make something bigger than it needs to be basically.

As for other cards, this varies by motherboard on how it is wired and keyed. Some MoBo's M.2 slots can be used as a traditional MiniPCIe slot in which case any MiniPCIe cards will work in it. That is basically just WiFi/Bluetooth cards.

[xwrench3]

WOW! first off, thanks for all the fast responses. second, it looks like we both need to do some investigation on this. i thought that (i did not know there was more than one type, and i do not think my son did either) M2 drives were faster, and he thought they were slower (i asked him about them last week).  we would both be installing them in desktops. he has a custom home built gaming rig using an Asus Z97- something mother board,  with an overclocked Intel i7 4770k and i am now doing a major revamp of my old system. i have not yet decided on a motherboard, so this is just one more in a long list of items to check for.

[xwrench3]

P.S, THANKS to Mecami to the link to Computer Shopper. i remember reading an article in a copy of that like 20 years ago. and i had completely forgotten about them.  it was a good article back then, and i was impressed.