One of these solutions was the NVM-express protocol, which, according to experts, has revolutionized the use of solid-state non-volatile memory. What is NVMe and what benefits does it bring with it?
The speed of the computer largely depends on the speed of reading data from media and the speed of command processing. No matter how high-performance the operating system as a whole is, everything can be negated by a regular hard drive, which makes programs slow down when opening or "think" when performing large tasks. Not to mention the fact that HDD has practically exhausted its potential for increasing the volume of information storage and therefore has become unpromising. And the mechanical drive is even more outdated and slowed down the development of computer technology.
And now SSDs came to replace the HDD - solid-state drives, non-volatile non-mechanical storage devices. The first SSDs hit the market in the second half of the 2000s. Soon enough, they began to compete with hard drives in terms of volume. But for a long time they could not fully reveal their potential and advantages in speed, parallelism of calls to cells, because the existing interfaces and protocols were built according to old standards designed to support HDD drives via SATA interfaces and even more ancient SCSI (SAS).
The next step in unlocking the potential of non-volatile memory was the transition to PCI-express buses. But for them, by that time, new industrial standards had not yet been developed. And in 2012, the first computers were released that implemented the NVM-express protocol.
, NVMe — . , — .
Therefore, the phrase "NVMe drive" is not entirely correct, and the comparison like "HDD - SSD - NVMe" is absolutely erroneous and misleads the user who is just getting acquainted with the topic. It is correct to compare HDD with SSD on the one hand, SSD connected via SATA interface (via AHCI protocol) and SSD connected via PCI-express bus using NVM-express protocol, on the other. Comparing HDDs to SSDs is probably no longer interesting to anyone. Everyone understands the difference, and everyone is well aware of the benefits of the latter. Unless to mention some (very striking) benefits. Compared to hard drives, solid-state drives are smaller and lighter, soundless, and the complete absence of mechanical drives makes them much more resistant to damage (for example, when dropped) and simply increases their service life.
Comparing the capabilities of SSD with the old bus and the old protocol and SSD on the PCIe bus with NVMe protocol is certainly of much more interest and will be useful to everyone who is used to keeping up to date with new products, those who are going to buy a new computer and even those who, for example looking for the best hosting.
The SATA interface, as already mentioned, was created for hard drives, the head of which can physically access only one cell at a time. It's no surprise that SATA devices only have one channel. For SSDs, this is deplorably small, because one of their advantages is support for parallel streams. The SSD controller also manages the initial positioning, which is another significant benefit. The PCI-express bus provides multi-channel operation, and the NVMe protocol realizes this advantage. As a result, data stored on solid-state drives is passed through 65,536 concurrent control queues, each of which can contain more than 65,536 commands simultaneously. Compare: SATA and SCSI can only use one queue, supporting up to 32 and up to 254 commands respectively.
In addition, the old interfaces require two calls to RAM to execute each command, and NVMe manages to do this in one go.
The third significant advantage is interrupt handling. The NVMe protocol was developed for modern platforms using multi-core processors. Therefore, it incorporates parallel thread processing, as well as an optimized queuing and interrupt handling mechanism, which allows for a higher level of performance. In other words, when a command with a higher priority appears, its execution starts faster.
Numerous tests carried out by various organizations and experts prove that NVMe SSDs work on average 5 times faster than when SSDs are connected via old interfaces.
Now about whether everyone has access to SSDs implemented on PCIe with the NVMe protocol. And it's not just about cost. For the price, such a realization is still noticeably higher, although the prices for computer components, as you know, are high only at the very beginning of sales and tend to decline quite rapidly.
We are talking about constructive solutions, about what in the professional language is usually called "form factor" . In other words, in what form are these components produced by manufacturers. There are three form factors currently on the market .
The first is called "NVMe SSD". It is an expansion board and connects to the same slots as the video card. This is unsuitable for a laptop. However, as for many stationary computers, since more and more of them are assembled on compact motherboards, where there are often two or even one PCIe slots (which is usually occupied by a video card).
The second form factor is U2. Outwardly, it resembles a regular hard drive, but much smaller in size. U2 is usually used on servers, so the average user shouldn't buy it.
The third is M2 . This is the most evolving form factor. It is actively used in laptops, and recently it has already been implemented on some motherboards for stationary PCs. However, when purchasing an M2 for yourself, you should be very careful, because SATA SSDs are still produced in this form factor.
However, attentiveness is also needed when assessing the feasibility of acquiring for yourself any of the named form factors. First, you should assess whether your laptop or PC motherboard has the right slots. And even if they are, does your computer have a powerful enough processor, because a weak processor will still prevent you from experiencing the advantages of an SSD. If you have all this and besides, you often operate with large amounts of data, of course, an NVMe SSD is what you need.
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