M.2 genarations

[wizzio]

I am doing some school work and my task is to look upp all diferent veriations of m.2 and what base speed they have, Ive heard about gen3 and gen but not gen1 and gen 2 do these exist. And last what are the base speed for all the diferent generations.

[FloRolf]

Uhm well you aren't researching M.2 generations here but rather pcie. There were pcie 1 (1.1), 2 and now we have 3 and 4.

M.2 is relatively new so there isn't really anything going on in terms of generations. It's just that they started with using pcie3.0 lanes and now (on amd at least) they use pcie4.0 lanes. 

[jaslion]

Gen1,2,3 and 4 basically just stand for what pcie generation they use. So gen 1 doesn't exist as well m.2 storage did not exist back then.

 

The first ones where based on pcie 2.0. So basically it's as simple as. Pcie 2.0 m.2 at x2 means it is a pcie 2.0 x2 link thus: 1Gb/s A x4 link is 2Gb/s.

[Coolmaster]

M.2 has only ever used PCIe gen 3 or gen 4. AIC cards used a different form factor but gen 2 and gen 3 PCIe. Your project is probably to compare SATA M.2 to PCIe gen 3 and gen 4 and maybe B + M to just M keyed M.2 drives.

[wizzio]

1 minute ago, Coolmaster said:

M.2 has only ever used PCIe gen 3 or gen 4. AIC cards used a different form factor but gen 2 and gen 3 PCIe. Your project is probably to compare SATA M.2 to PCIe gen 3 and gen 4 and maybe B + M to just B keyed M.2 drives.

Thank you very much this was helpful

[minibois]

14 minutes ago, wizzio said:

I am doing some school work and my task is to look upp all diferent veriations of m.2 and what base speed they have, Ive heard about gen3 and gen but not gen1 and gen 2 do these exist. And last what are the base speed for all the diferent generations.

Understanding M.2 is about understanding the physical and electrical interface, plus the amount of lanes.

 

There are two types of M.2 drives:

- M.2 SATA, which will typically be SATA III speeds, to up to around 550MB/s

- M.2 PCIE drives, which come in PCIE generation 3 and 4.

 

M.2 in general has not been around for too long, but PCIE has been around for a lot longer. Obviously starting in generation 1.

The way PCIE works, is you have a generation and you have an amount of lanes. The generations and the amount of lanes decide the max. speed.

This page shows the generations, lanes and their speed: https://en.wikipedia.org/wiki/PCI_Express#History_and_revisions

 

Simply put, M.2 PCIE drives typically have 4 lanes and have PCIE 3.0/4.0. That gives a theoretical max speed of around 4GB/s and 8GB/s on PCIE 3.0 and 4.0 respectively.

Your CPU and chipset have a certain amount of PCI lanes, which will be divided among the different ports on the motherboard. The way these lanes are divided and possibly shared among slot differs, but there are boards which may only have a M.2 PCIE generation 2.0 x2 or x4 connector, which can limit the speed of transfer.

 

The beauty of PCIE - whether M.2 or just in general - is the backwards and forwards compatibility. A newer drive works with an older slot and vice versa. It's just that they will work at the lower of the two speeds.

 

In short:

- M.2 comes in SATA and PCIE

- SATA is generally SATA 3, PCIE is gen 3 and 4

- Boards have a certain M.2 PCIE generation per slot

- The amount of lanes + generation describes the maximum speed of a slot/SSD

- Speeds are determined by the lowest speed in the chain (between board M.2 PCIE slot and SSD)

- Generally max speeds double by two each generation and double by two with double the lanes (i.e. PCIE 3.0 x16 is about equal to PCIE 4.0 x8)

- M.2 PCIE drives are generally PCIE generation 3 or 4, with 4 lanes.

 

How to get the max speed:

- Look up PCIE generation + lanes of SSD and see the max speed

- Look up PCIE generation + lanes of the motherboard and see the max speed

- Look up the SSD reported read/write speeds on the datasheet

Now take the lowest of all and that's the speed it will run at, at best.

[Moonzy]

M.2 is the socket type

Generation is the pcie generation, which dictates the bandwidth

I'm not sure if this is true but some chipset may limit m.2 speeds to gen 2 if it's going thru the chipset

But you won't find much m.2 below gen3 because it's released well into pcie 3.0 era

[wizzio]

so there is basically 2 different types of M.2 which is Sata m.2(around 500 MB/s) and PciE m.2 were the speed is base on the generarion och PciE speed?

[Coolmaster]

1 minute ago, wizzio said:

so there is basically 2 different types of M.2 which is Sata m.2(around 500 MB/s) and PciE m.2 were the speed is base on the generarion och PciE speed?

More or less, the SATA m.2 is using the same interface as the SATA connector to Hard drives and SSDs just in a different form factor. And there is always a ton of depth that can be explored with anything tech.

[minibois]

16 hours ago, wizzio said:

so there is basically 2 different types of M.2 which is Sata m.2(around 500 MB/s) and PciE m.2 were the speed is base on the generarion och PciE speed?

Yea, basically.

Keep in mind though, the M.2 SATA "around 500MB/s" is still based on what the manufacturer makes. They can decide to make a crap SSD that is slower, but most of them are around 500MB/s read/write.

M.2 PCIE's max speed is based on the generation and lanes, but of course also by the type of SSD a manufacturer makes.

The Kingston A2000 and Samsung 970 EVO Plus both use a M.2 PCIE gen 3 x4 connection, but they just go at 2200/2000MB/s read/write and 3500/3000MB/s read/write respectively.

 

By the way, M.2 is not only used for SSD's. It can also be used for WiFi cards.

That brings in another aspect of M.2: keying.

There is B-key, M-key, B+M-key, E-Key and A-key.

 

M-key, B+M-key and E-key are the most common.

M-key supports: M.2 PCIE (x4) and SATA drives (most commonly this is used on M.2 PCIE drives_

B+M key supports: M.2 SATA, PCIE x2, PCIE x4 (mostly commonly used on M.2 SATA)

E-key is generally used for WiFi cards.

 

You can recognize the different standards by the amount of pins and notches:

 

Sorry if this is just a lot of information, but even though M.2 is a relatively new connector in PC's, there is a LOT of variations of drives.