NVMe drives are a major task in computer storage right now and for good reason. An NVMe solid-state drive (SSD) not only leaves most older SSDs in the dust, it also glows rapidly compared to standard 3.5- and 2.5-inch drives.
NVMe vs. SATA III
For example, take 1TB of Samsung 860 Pro, a 2.5-inch SSD with a maximum sequential read speed of 560 megabytes per second (MB / s). Its successor, the NVMe-based 960 Pro, is more than six times faster than that, with a top speed of 3,500 MB / s.
This is because the pre-NVMe devices connect to a PC via SATA III, the third revision of serial ATA computer bus interface. NVMe, meanwhile, is the host control interface for newer, more advanced SSDs.
SATA III and NVMe are the terms most commonly used to distinguish between the old school and the new hotness that everyone wants. However, NVMe is not the same type of technology as SATA III.
We come to why we use the terms "SATA III" and "NVMe" to compare the technologies later.
What is SATA III?
In 2000, SATA was introduced to replace the Parallel ATA standard that preceded it. SATA offered higher speed connections, which meant much improved performance compared to its predecessor. SATA III was rolled out eight years later with a maximum transfer rate of 600 MB / s.
SATA III components use a specific type of connector to record a laptop, and a specific type of cable to connect to a desktop PC motherboards.
When a device is connected to the computer system via SATA III, only half is done. For the device to talk to the system, it needs a host control interface. This job belongs to AHCI, which is the most common way for SATA III devices to talk to a computer system.
For many years, SATA III and AHCI performed admirably, even during the early days of the SSD. However, AHCI was optimized for high latency, non-latency, non-volatile, non-volatile storage media such as the SSD, a representative from the unit's manufacturer Kingston explained.
Solid-state devices became so fast, they eventually saturated the SATA III connection. SATA III and AHCI simply could not provide enough bandwidth for ever more capable SSDS.
With drives and capacity expanded, the search for a better alternative was. And fortunately, it was already used on computers.
What is PCIe?
PCIe is another hardware interface. It is best known as a graphics card on a desktop computer, but it is also used for sound cards, Thunderbolt expansion cards and M.2 devices (more on the latter).
If you look at a motherboard (see above) you can easily see where the PCIe slots are, they usually come in variants x16, x8, x4 and x1.These numbers indicate how many fields of data transfer a place has. the more data you can move at any time, which is why graphics cards use x16 slots.
There is also an M.2 slot in the image above, just below the upper x16 slot. can use up to four lanes, they are thus x4.
The most important PCIe slots in all computers have lanes connected to the CPU for best performance and the rest of the PCIe slots are connected to the chip. This also supports a fairly fast connection to the CPU, but not as fast as the direct connections.
There are currently two generations of PCIs used: 3.0 (the most common) and 4.0. From mid-2019, PCIe 4.0 was brand new and supported only on AMD's Ryzen 3000 processors and X570 motherboards. Version 4 is, as you might expect, faster.
Most components do not yet measure the maximum bandwidth for PCIe 3.0. So while PCIe 4.0 is impressive, it is not yet necessary for modern computers.
RELATED: PCIe 4.0: What's New and Why It Matters
NVMe Over PCIe
PCIe is thus like SATA III; they are both used to connect individual components to a computer system. Just like SATA III, AHCI needs before a hard drive or SSD can communicate with a computer system, PCIe-based devices rely on a host controller called non-volatile memory expression (NVMe).
But why don't we talk about SATA III versus PCIe devices, or AHCI versus NVMe?
The reason is quite simple. We have always referred to units as SATA-based, such as SATA, SATA II and SATA III – no surprise there.
When device manufacturers started making PCIe devices, there was a brief period when we talked about PCIe SSDs
However, the industry had no standards for collecting in the same way as with SATA devices. Instead, as Western Digital explained, companies used AHCI and built their own drivers and firmware to run these devices.
It was a mess, and the AHCI was still not good enough. As Kingston explained to us, it was also more difficult for people to adopt drives that were faster than SATA because they had to install special drivers rather than a plug-and-play experience.
Finally, the industry adopted the standard that became NVMe and replaced AHCI. The new standard was so much better, it made sense to start talking about NVMe. And the rest is, as they say, history.
NVMe was built with modern PCIe-based SSDs in mind. NVMe drives can accept significantly more commands simultaneously than SATA III mechanical hard drives or SSDs. Combined with lower latency, NVMe drives are faster and more responsive.
What do NVMe devices look like?
If you are shopping for an NVMe based drive today, what you want is an M.2 gum stick. M.2 describes the unit's form factor – or for our purposes what it looks like. M.2 units usually have up to about 1 TB of storage space, but they are small enough to hold between the thumb and forefinger.
M.2 devices connect to special M.2 PCIe card slots that support up to four lanes of data transfer. These devices are usually NVMe-based, but you can also find M.2 devices that use SATA III – just read the packaging carefully.
SATA III-based M.2 is not so common today, but they do exist. Some popular examples are WD Blue 3D NAND and Samsung 860 Evo.
RELATED: What is M.2 Expansion Slot and how can I use it?  Should you dump SATA III drives?
While NVMe is fantastic, there is no need to give up the SATA III devices yet. Despite the limitations of SATA III, it is still a good choice for secondary storage.
For example, anyone who builds a new computer would do well to use an M.2 NVMe drive for their boot drive and primary storage. He could then add a cheaper hard drive or 2.5-inch SSD with greater capacity as secondary storage.
It may be a nice idea to have all your storage over PCIe. At present, NVMe units are limited to about 2 TB. Higher capacity is also prohibitively expensive. A budget 1 TB, M.2 NVMe drive usually costs about $ 100 (which is about what a 2 TB high performance SATA III hard drive costs).
Pricing can of course change as we get even higher capacity M. 2 units. Kingston said we can expect to see M.2 drives with 4 and 8 TB capacity around early 2021.
Until then, the combination of M.2 with secondary SSDs and hard drives is the best option.
The same idea applies to laptops. If you buy a new rig, look for one with NVMe flash storage and an extra 2.5-inch compartment for a SATA III hard drive or SSD.
But not all NVMe devices are created equal. It definitely pays to read reviews on your target device before buying one.
If you have a recent desktop or laptop computer, there are likely to be M.2 slots that support NVMe. Upgrading your computer is well worth it!