Memory type
The type of the main memory of the drive determines the features of the distribution of information over hardware cells and the physical features of the cells themselves.
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MLC. Multi Level Cell memory based on multi-level cells, each of which contains several signal levels. MLC memory cells store 2 bits of information. Has optimum indicators of reliability, power consumption and productivity. Until recently, the technology was popular in entry-level and mid-range SSD modules, now it is gradually being replaced by more advanced options in the manner of TLC or 3D MLC.
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TLC. The evolution of MLC technology. One Flash Memory Triple Level Cell can store 3 bits of information. Such a recording density somewhat increases the likelihood of errors compared to MLC, in addition, TLC memory is considered less durable. A positive feature of the nature of this technology is its affordable cost, and various design tricks can be used to improve reliability in SSDs with TLC memory.
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3D NAND. In a 3D NAND structure, several layers of memory cells are arranged vertically, and interconnections are organized between them. This provides greater storage capacity without increasing the physical size of the drive and improves memory performance due to shorter connections for each memory cell. In SSD drives, 3D NAND memory can use MLC, TLC or QLC chips - more
...details about them are described in the corresponding help paragraphs.
— 3D MLC NAND. MLC-memory has a multilayer structure — its cells are placed on the board not in one level, but in several "floors". As a result, manufacturers have achieved an increase in storage capacity without a noticeable increase in size. Also, 3D MLC NAND memory is characterized by higher reliability than the original MLC (see the relevant paragraph), at a lower manufacturing cost.
— 3D TLC NAND. "Three-dimensional" modification of the TLC technology (see the relevant paragraph) with the placement of memory cells on the board in several layers. This arrangement allows you to achieve higher capacity with smaller sizes of the drives themselves. In production, such memory is simpler and cheaper than a single-layer one.
— 3D QLC NAND. Quad Level Cell flash type with 4 bits of data in each cell. The technology is designed to make SSDs with large volumes widely available and finally retire traditional HDDs. In the 3D QLC NAND configuration, the memory is built according to a “multi-level” scheme with the placement of cells on the board in several layers. "Three-dimensional" structure reduces the cost of production of memory modules and allows you to increase the volume of drives without compromising their weight and size component.
— 3D XPoint. A fundamentally new type of memory, radically different from traditional NAND. In such drives, memory cells and selectors are located at the intersections of perpendicular rows of conductive tracks. The mechanism for recording information in cells is based on changing the resistance of the material without the use of transistors. 3D XPoint memory is simple and inexpensive to produce, and offers much better speed and durability. The prefix "3D" in the name of the technology says that the cells on the crystal are placed in several layers. The first generation of 3D XPoint received a two-layer structure and was made using a 20-nanometer process technology.NVMe
NVMe drive support.
NVMe is a communication protocol designed specifically for SSD modules and used when connected via the PCI-E bus. This protocol was developed to eliminate the shortcomings of earlier connection standards (like SCSI or SATA) — primarily low speed, which did not allow realizing the full capabilities of solid-state memory. NVMe takes into account the key advantages of SSD — independent access, multithreading and low latency. Support for this protocol is built into all major modern operating systems; it works not only through the original PCIe interface, but also through M.2 (see Form Factor). And the U.2 connector was generally created specifically for NVMe SSDs (although the presence of this connector in itself does not mean compatibility with this protocol).
Write speed
The highest speed in write mode characterizes the speed with which the module can receive information from a connected computer (or other external device). This speed is limited both by the connection interface (see "Connector"), and by the characteristics of the device of the SSD itself.
Read speed
The highest data exchange rate with a computer (or other external device) that the drive can provide in read mode; in other words —
the highest speed of information output from the drive to an external device. This speed is limited both by the connection interface (see "Connector"), and by the characteristics of the device of the SSD itself. Its values can vary from 100 – 500 MB / s in the slowest models to 3 Gb / s and higher in the most advanced ones.
Shockproof
A parameter that determines the resistance of the drive to drops and shocks during operation. Measured in G — units of overload, 1 G corresponds to the usual force of gravity. The higher the G number, the more resistant the device is to various kinds of shocks and the less likely it is to damage the data in it, say, in the event of a fall. This parameter is especially important for external drives (see Type).
Manufacturer's warranty
Manufacturer's warranty provided for this model.
In fact, this is the minimum service life promised by the manufacturer, subject to the rules of operation. Most often, the actual service life of the device is much longer than the guaranteed one. However, keep in mind that the warranty often includes additional terms, such as “[so many years] or until the TBW is exhausted” (for more on TBW, see above).
Specific warranty periods may vary even for similar drives from the same manufacturer. The most popular options are
3 years and
5 years, however, there are other figures — up to
10 years in the most expensive and high-end models.
Cable included
The type of cable that comes with the drive.
This parameter is relevant only for external models (see "Type"). The type of cable is indicated by the types of connectors at its ends, with the plug for connecting to the drive being the first, and the plug for connecting to the computer being the second. Specific types of connectors can be as follows:
— USB A. Plug for traditional full-size USB ports — such as those provided in most computers and laptops. Actually, such a plug is used only at the “computer” end of the cable — USB A connectors are too bulky for the drives themselves.
— USB-C. The newest of modern USB connectors. Unlike its predecessors, it has a two-sided design — the plug can be inserted into the connector by either side. Very compact, making it suitable for installation in the drive case; however, it is also found in computers/laptops, so USB-C plugs can be provided on one or both sides of the cable.
— Micro B. Plug under the microUSB connector; such a connector is familiar to many from portable gadgets like smartphones and tablets, it is also found in SSD drives. Actually, the micro B plug is provided only on the side of the drive — this connector is practically never found in computers.
— MiniUSB. Another smaller version of the USB plug, in many ways similar to the micro B described above. Nowadays it is considered obsolete and has practically fallen into disuse.
The most common bundled c
...able options are USB-C — USB A, USB-C — USB-C, micro B — USB A and mini USB — USB A. Some drives that have a USB-C connector are equipped with two types of wire at once — with USB-C and USB A at the "computer" end.Shockproof
The presence in the drive of enhanced protection against shocks and concussions.
SSD modules themselves are pretty shock-resistant; the same feature is indicated if the drive is specially reinforced in order to withstand falls and other “troubles” as much as possible.
The impact-resistant housing is relevant primarily for outdoor models (see "Type").
Material
The material from which the drive housing is made. This parameter is relevant mainly for external models (see "Type"), because the internal ones are protected by the computer case and under normal conditions do not come into contact with the environment.
— Plastic. Inexpensive and at the same time quite practical material. Plastic is inferior to metal in terms of strength, but it is quite reliable (up to the possibility of being used in shock-resistant models), and besides, it is not afraid of moisture. In addition, this material easily takes on a wide variety of shapes and colours, which "makes life easier" for designers and allows you to create original looking devices. Because of this, most cases for SSD drives are made of plastic.
— Metal. From a practical point of view, metal, on the one hand, is stronger than plastic, on the other hand, it is more difficult to process and more expensive; however, high strength is rarely required in fact. Therefore, the metal case is typical mainly for fairly advanced solutions.
