What is the difference between SATA, M.2 and PCIE in an SSD?

Question

Iron

I do not understand very well what is the difference between SATA, M.2 and PCIE in SSDs.
Let me explain using the example of a conventional SSD (2.5).
A regular SSD has a connector and an interface. SATA connector. Interface SATA1, SATA2, SATA3.
That is, via a connector with the SATA form factor, information can be exchanged via the SATA1..SATA3 interface. Now it is SATA3 with a maximum speed of up to 6 Gb / s.
But relatively recently, SSD drives have appeared in the form of boards connected to a PCIE or M.2 connector.
If we disassemble the SSD connected to PCIE, we will see an adapter for M.2 with a card (SSD) inserted into it.
There are questions.
1) M.2 connector on new boards. What is its interface? And so what are the speeds?
2) Why did they invent M.2 when there is already PCIE 3.0 x16? Why not place another PCIE 3.0 x16? Yes, they do this on gaming motherboards, so make 3-4 PCIE, why invent a new one?
3) What about PCIE x1? It seems that you can insert an SSD there.
What is the difference between SATA, M.2 and PCIE in an SSD?

Answer 1

1) M.2 connector on new boards. What is its interface? And so what are the speeds?

Either SATA or PCI. PCI is much faster, I have PCI-4, 2100 MB / s read, 1200 write.
Small, compact, fits anywhere, not very high power consumption.

3) What about PCIE x1? It seems that you can insert an SSD there.
What is the difference between SATA, M.2 and PCIE in an SSD?

Don't confuse the PCI connector (big and long) with M2, which works like PCI.

Answer 2

You can ask a similar question, why does the processor manufacturer change the socket with each new line? First of all, this is marketing to stimulate sales of motherboards, and secondly, this is a technical process.
M.2 is a compact form and speed is similar to PCIE. It's much easier to plug in an "invisible" M.2 than to place and connect a cable for SATA. About PCIE is similar, even if the speed is the same, then not all devices have the ability to use it, for example, on the same laptops.
Manufacturers cannot even agree on a power connector for the phone, not to mention interfaces. Each interface has a future for now:
- You need to connect 8 drives, choose SATA
- Do you want a compact solution - M.2
- Do you need speed or do you want to connect a pair of M.2 - PCIE
For speed on the M.2 interface, look at the manual for the motherboard, they usually write speeds there.
Therefore, summing up your question: The whole reason is marketing and the technical process, but we should not forget about the convenience for the user (device).

Answer 3

1) M.2 connector on new boards. What is its interface? And so what are the speeds?

m.2 in most cases can work both as SATA and as PCI-E x4
m.2 pci-e takes 4 pci-e lanes, what's the point of occupying a 16 lane slot with one drive using only 4 lanes? and pci-e lines in desktops/servers are not endless. desktops usually have 24, servers and workstations have 40+
it is possible, the speed will be lower than that of m.2

Answer 4

1) The M2 connector is a mechanical connector. Mechanical interface - M2.
It can be connected to a sata controller, or to a PCI-E bus.
Therefore, the data transfer interface can be anything - sata, nvme, etc.
2) The size is wrong. Too big and uncomfortable.
3) You can.
For example, the M2 connector is connected to the PCI-E bus and transmits data via the NVMe protocol.
Or an M2 connector connected to a sata controller, and transmitting data using the AHC protocol |

Answer 5

https://en.m.wikipedia.org/wiki/M.2

Answer 6

On SATA, a maximum of 600 megabytes / s (it doesn’t matter which disk, even m2), and if there are several disks and are actively loaded, you won’t get this speed either (it rests on the controller and the interface of the controller itself).
On NVMe - already now 3500 megabytes / sec in the "free sale". At what such 2 disks in work will almost not interfere with each other.
Why: well, for example, to make a server with several virtual machines for "5 kopecks" (domain controller, file server, SQL server, ATSka, WWW server, terminal server for a dozen active users, etc.) and also hang a RAID on it array. Everything will turn out sadly on SATA, even if you cram several disks.