In the past two years, in the 618 promotion, SSD (solid state drive) is a popular consumer product category. Earlier last year, the SSD market also ushered in a wave of low prices, triggering a rush to buy.
Although the price of SSD has rebounded to a certain extent this year, from the perspective of the price fluctuation trend throughout the year, 618 is undoubtedly a time to pay attention to buying.
1. Understanding SSD (Solid State Drive)
Before choosing a suitable and cost-effective SSD, you may wish to understand the various parameters of the SSD and establish a basic understanding.
There are five aspects worth knowing when choosing an SSD, which are interface shape, transfer protocol, transport bus, flash memory particles, and TBW (total amount of data written).
Interface modeling
The most common SSD interface shapes can be divided into two categories: SATA interface and M.2 interface.
These two interfaces are relatively recognizable, with the larger one being the SATA interface and the smaller one being the M.2 interface. The M.2 interface can also be subdivided into two different shapes: B-Key and M-key, as shown in the figure:
Protocols & Buses
The protocol and bus are both important parameters of the SSD.
The protocol can be understood as a "rule", and only when the same or compatible protocol is adopted between devices can data be transmitted; The bus, on the other hand, is the path through which data is transferred from the SSD to the CPU.
Use a simple analogy to help you understand these two concepts. The bus is like a highway, and the protocol is the speed limit sign for the road.
The speed (rate) at which a car (SSD) can travel (transmit) depends on how wide the road (bus) is, but is also limited by speed limit signs (protocols).
To get back to the point, there are two common protocol types for SSDs, namely NVMe protocol and AHCI protocol. The two common bus types are PCIe bus and SATA bus.
Since these concepts are relatively complex, we will not elaborate on them here, but we will borrow the metaphor just now:
The NVMe protocol is equivalent to the 120km speed limit, while the AHCI protocol is equivalent to the 40km speed limit, and the former is faster.
The PCIe bus is equivalent to a wide lane that can pass through two cars at the same time, and the SATA bus is equivalent to a narrow lane that can pass only one car.
If the SSD uses the PCIe bus + NVMe protocol, it will undoubtedly have the fastest transfer speed.
Flash particles
Flash memory particles have a great impact on the experience of using SSDs, including speed, endurance, and even price. There are four main types of flash memory particles: SLC, MLC, TLC, and QLC.
The comparison of the four storage chips is as follows, among which TLC particles are also widely used in SSDs due to their relatively moderate performance and price.
TBW (Total Data Written)
TBW (Total Data Written) represents the amount of data that an SSD can carry, and is an indicator that quantifies the service life and quality of an SSD.
The storage medium of the SSD is a flash memory chip, and the data is stored on the flash memory unit of the chip. Whenever a data is read or written, the flash memory cell is erased. The process of repeated erasing will affect the service life of the SSD.
TBW can be calculated with the help of the following formula:
However, in fact, ordinary users do not need to calculate TBW by themselves, and this parameter will be reflected in the product detail page of the general SSD (as shown in the figure below), the larger the parameter, the more durable the SSD.
Source: YMTC official website
2. How to choose SSD?
After some basic understanding of SSD, the next part is how to buy SSD. In the purchase process, we can first look at the flash memory particles and then pay attention to the rate, which can basically make the right purchase decision.
To buy an SSD is to buy a pellet
There is also a saying in the storage world: buying an SSD is buying a particle. First of all, we can pay attention to the production and packaging manufacturers of SSD flash memory particles, which is related to the performance of SSD.
At present, there are mainly these manufacturers that have the ability to produce storage particles: Samsung, Kioxia, Western Digital, Micron and the domestic Yangtze River Storage, and these large manufacturers basically have their own SSD brands.
Source: YMTC official website
Upstream manufacturers often supply the best quality flash memory particles to their own SSD products, for example, Zhitai is the SSD brand of YMTC, and the original particles used by YMTC are naturally used.
The advantages of the original particle are very obvious: the particle has been strictly tested and packaged by the original factory, and the failure rate is extremely low, and the SSD using the original particle means that it is more stable and durable.
Source: YMTC official website
In addition to particle manufacturers, there are some manufacturers who do not have the ability to manufacture particles, but have the technology to encapsulate particles, which are called "module factories", mainly including: Phison, Huirong, Kingston, Longsys, Lianyun, ADATA and so on.
Some of the above-mentioned manufacturers have their own SSD brands, and they will use large manufacturers that test and package their own particles. In addition, these manufacturers will also sell their own packaged pellets to other downstream consumer brands.
Compared with the original particles, the quality of the encapsulated particles is slightly inferior, which is caused by the differences in testing standards and packaging methods of different manufacturers.
To put it simply, when paying attention to performance and durability, the upstream brand that uses the original particle is preferred when purchasing SSD;
If you are looking for cost performance, SSD products that use packaging particles are also a good choice, which can meet the daily basic storage needs, and the difference between them and the original particle SSD is not as obvious as imagined.
SSD rates look at it this way
As we mentioned earlier, the transport bus is like a road, and the transport protocol is like a speed limit marker, and together they determine how fast the car (SSD) can run.
It should be noted that the bus version represents the upper limit of the theoretical speed that the SSD can run, and is not equivalent to the speed of the SSD itself, and the SSD rate also needs to be determined by the protocol version.
In the current storage market, mainstream SSD products mainly use PCIe 3.0×4 bus, with a theoretical maximum speed of 4GB/s. Some high-end SSDs use PCIe 4.0×4 with a theoretical maximum speed of 8GB/s.
Source: Samsung's official website
In terms of protocol versions, NVMe 1.3, NVMe 1.4, and NVMe 2.0 are the main mainstream SSD products.
Choose the highest possible SSD protocol version, such as NVMe 1.4 or even 2.0, the higher the version, the more you can unlock the full performance of the bus.
An SSD using PCIe 4.0×4 bus and NVMe 1.4 protocol can have an actual transfer rate of up to 7000MB/s, which basically meets the performance limit of the PCIe 4.0×4 bus after removing the necessary losses.
An SSD using the PCIe 3.0×4 bus and NVMe 1.4 protocol can reach an actual rate of 3500MB/s, which is also close to the upper limit of the PCIe 3.0×4 bus.
SSDs are more rational to buy on demand
High performance means high efficiency, but not every user needs an SSD with PCIe 4.0×4 bus and NVMe 1.4 protocol, after all, you get what you pay for, and high performance also means higher costs.
Ordinary PCIe 3.0×4 bus SSD, no matter what protocol version is used, the actual speed is basically above 3000MB/s, which can easily meet the daily data storage needs and is suitable for most public users.
PCIe 4.0×4 bus SSDs are more suitable for groups with frequent large file transfer needs, such as photographers, editors, gamers, and so on.
These people have a higher demand for efficiency, and PCIe 4.0×4 can meet the demand for efficiency with speeds of up to 7000MB/s.
In addition, Sony's PS5 game console can be externally expanded through SSD, but it requires a PCIe 4.0 or even higher SSD, so you have to use a PCIe 4.0×4 bus SSD, which you can pay attention to.
In addition to being used for expansion, SSD can also be used with a hard disk enclosure to form a storage device, compared with PSSD (finished mobile hard disk), the capacity can be selected by yourself, which is relatively flexible.
If it is used with a hard disk enclosure, the choice of SSD is also a bit particular. At present, the transmission bandwidth of mainstream hard disk enclosures is mostly 10Gbps, which translates to a rate of about 1250MB/s.
If it is a higher-end Thunderbolt enclosure or USB4 enclosure, the transfer bandwidth can reach 40Gbps, which translates to about 5000MB/s.
Therefore, in the choice of SSD, if it is a 10Gbps rate hard disk enclosure, an SSD with PCIe 3.0 can run up to the upper speed limit of the hard disk enclosure;
If it is a Thunderbolt hard disk enclosure or USB4 hard disk enclosure, you need to use a PCIe 4.0 SSD to take advantage of the 40Gbps ultra-high speed.
3. Summary at the end of the article
The purchase of SSD is not as complicated as imagined, choose the right brand, and then choose PCIe 3.0 or PCIe 4.0 SSD products according to your actual needs.
If you have other questions about purchasing SSD, please leave a message or private message in the background.