In the past two days, fans have been asking about purchasing SSDs. The editor was also curious to search for SSD brands currently in the industry. You wouldn’t know it if you didn’t search it, but you’ll be surprised when you search it and you’ll find nearly 200 brands.
So, what brand should you buy when buying an SSD? Is it possible to buy an SSD now?
1. Principle of solid state drive SSD
Let’s first understand the principle of solid-state drive SSD. The architecture is as shown below. We can clearly understand that solid-state drive is mainly composed of main control, DRAM cache and NAND flash memory. The main tasks that the main control is responsible for are Wear Leveling, Garbage Collection, Bad Block Management, ECC error correction, etc. At the same time, in the main control, the Host interface is connected to the host, and the Host and the solid-state drive The communication protocol between them can be PCIe, SAS or SATA, etc., and the NAND flash memory is connected to the NAND controller.
There is a big difference between solid-state drives and mechanical hard drives. Mechanical hard drives also include mechanical parts such as spindles, motors, disks, heads, and head arms. The heads write data to the disk channels by running the mechanical parts; while solid-state drives use the main control chip. Write data to the storage medium NAND flash memory. The difference in working principles also shows that the performance of solid-state drives is much better than that of mechanical hard drives.
The NAND media of SSD solid state drives is the core area of data storage and also determines the price trend of SSDs. Currently, the SSDs available in the market are basically TLC and QLC. The more potential states in NAND flash, it means that the intervals between different potential states are getting smaller and smaller, making it easier to cause read and write errors. In other words, QLC NAND is less reliable than TLC/MLC NAND, so the price gradually decreases: SLC>MLC>TLC>QLC.
- SLC: There is 1 bit in a cell and 2 potential states.
- MLC: There are 2 bits in a cell and 4 potential states.
- TLC: There are 3 bits in a cell and 8 potential states.
- QLC: There are 4 bits in a cell and 16 potential states.
2.SSD price trend
Judging from the overall trend, SSD prices will continue to decline. At present, the price of a single TB of SSD is still slightly more expensive than that of a mechanical hard drive. It is believed that with the subsequent popularity of QLC NAND media, the price of SSD will be the same as that of HDD in the next three years, or even lower.
Combined with some reactions in the NAND market in recent years, we can also see
- Since the third quarter of 2022, the NAND flash memory market has experienced oversupply. Among them, although the shipments of notebooks for consumer-grade SSDs have rebounded, for enterprise-grade SSDs, orders from China are being released one after another, which is expected to further stimulate shipments, and the month-on-month decline is expected to narrow to a decline; for UFS, the purchase volume is limited, and the average price is expected to be will fall month-on-month.
- According to data from different suppliers, starting from the second quarter of 2023, the inventory pressure of advanced processes above 128 layers has gradually increased, and some manufacturers have announced production cuts to reduce inventory.
According to data from TrendForce research institute, NAND prices will rebound in the fourth quarter.
Judging from the trend of online shopping platforms: SSD prices are indeed on a downward trend. The 618 promotion is the lowest in history, and the overall price is currently at a low level.
A hot-selling TOP1 M.2 NVME PCIe 4.0 2TB SSD: from the highest price of 1199, the price was 618 to the lowest 479, and it is currently rising to 599.
A domestic M.2 NVME PCIe 4.0 2TB SSD: from the highest price of 1299, the price was 618 to the lowest 879, and currently it is back up to 879.
M.2 NVME PCIe 4.0 2TB SSD from a major manufacturer: the price ranged from the highest price of 2399, priced at 618 to the lowest price of 999, and is now up to 1149.
3. How to choose SSD
If you buy a new computer directly, you basically don’t need to care about the shape inside the computer. You mainly focus on other aspects. This is mainly for scenarios where you want to upgrade the hard drive of your old computer.
First of all, you need to understand the interface of the existing storage hard drive on your computer. This is in the manual, or you should be able to see it by taking off the back cover of the computer. If there are girls who don’t know how to use computers, they can ask boys for help at this time.
In the PC scene, there are basically two common forms: mechanical hard drives have a 2.5-inch interface, and SSD solid-state drives basically have an M.2 interface. The interface lengths are different, the longer one is 2280, and the shorter one is 2230. When choosing an SSD, you must first confirm the form of your computer interface. Otherwise, you won’t be able to install it on your computer after you buy it.
In addition to the differences in physical interfaces, there are also differences in SSD interface protocols. The current mainstream SSD interface protocols are mainly SATA and PCIe.
SATA interface
The SATA interface is a serial interface that uses the IO queue protocol to achieve faster data transmission. In addition, the SATA protocol introduces more advanced features due to shifting the transmission mode from slow ATA to faster AHCI. For example, queued Trim commands, native command queue NCQ, and hot plugging of the same physical interface. Since the introduction of SATA in 2003, it has developed into three generations, and the transmission speed has increased from 1.5Gb/s to 6.0Gb/s. At present, the SATA protocol has basically no subsequent evolution and is basically in its final state.
PCIe interface
PCIe is a high-speed serial computer expansion bus standard. Compared with SATA, it has many improvements, such as higher maximum system bus throughput, fewer IO pins, smaller physical footprint and more Good bus device performance expansion. The PCIe bus is a high-speed differential bus that uses end-to-end data transmission. As PCIe technology continues to develop and advance, PCIe Gen3, which was released in 2015, is currently the most widely used on the market. In June 2017, PCIe Gen4 was released, and Gen4 solid-state drives are now available on the market. In 2019, Gen5 was also released, with a speed of 128GB/s and increasingly powerful performance. However, Gen5 SSD has not yet been launched on a large scale, so everyone still needs to wait patiently.
Here is a point where it is easy to get confused. There is another term: NVMe. NVME is a protocol that runs on the PCIe physical bus. Simply put, NVMe over PCIe. In the market, we often see these two words appearing together, and many scenes equate these two words. For ordinary hard disk users, as long as they know the terms pcie ssd and nvme ssd, they are directly equivalent. (If you are interested in the pcie/nvme protocol and want to learn more about it, you can follow the [Storage Essay] WeChat official account or the CSDN blog official website channel to read the relevant popular science articles. I believe you will gain a lot~).
SSD lifespan
When we choose solid-state drives, we often see the promotion page showing **TBW and a 3-year or 5-year warranty. How do you understand TBW here?
The full name of TBW is Terbytes Written, which represents the amount of data written during the entire service life of this solid state drive. This is an important parameter that reflects the life and reliability of solid-state drives.
For example, in the picture above, the product claims that the lifespan of an SSD supporting 1TB capacity is 600TBW. In other words, when the amount of data written to this solid-state drive exceeds 600TBW, the life of the SSD is basically over, and the manufacturer no longer guarantees reliability. However, the disk may not be abnormal at this time, but there is already a risk of data damage. It is necessary to complete the data backup in time and replace the disk with a new one.
This disk has a warranty period of 5 years. If converted in this way, the average amount of data written every day = 600TB/(5 years * 365 days/year) = 328GB
In general, the larger the TBW value, the higher the reliability and the longer the service life, but the corresponding price will naturally increase.
4.Usage scenarios
Based on common usage scenarios, we can roughly classify users into four categories: business needs, content creators, gamers, and students. For these four different groups of people, the requirements for the characteristics of solid-state drives are also different. The specific comparison reference is as follows:
When choosing usage scenarios, you should also consider several references in SSD performance: sequential read and write performance, random read and write performance
- Sequential read and write performance: Mainly suitable for large file transfers, such as movies and files several GB in size. In this scenario, the read and write performance of the sequential scenario needs to be considered.
- Random read and write performance: It is mainly suitable for small-block file transfers. This is the scenario most commonly used by individuals.
SSD product claims generally indicate the maximum sequential read and write bandwidth, and 4K small block random read and write IOPS (for the convenience of bandwidth comparison, IOPS*4K can also be converted into bandwidth). For example, this SATA SSD has a sequential write bandwidth of 520MB/s and a 4K random write IOPS=70K. The converted bandwidth is 4K*70K=280MB/s.
There is still a certain difference between random write and sequential write bandwidth. You must pay attention to this. The maximum bandwidth claimed by the manufacturer is usually a sequential read and write scenario.
Conclusion
In general, if you want to choose a hard drive that suits you, you need to consider many factors. If you are a wealthy person, just pretend I didn’t say anything and just buy the most expensive one~