How to choose SSD?

Using Solid State Drive (SSD for short) as an important storage medium has gradually become the mainstream. There are many brands of solid state drives on the market, and they are uneven. How to choose a suitable solid state drive with a limited budget?

Check the interfaces supported by the motherboard

Before purchasing a solid-state drive, the first thing to do is to confirm the interface supported by your motherboard: confirm the type of solid-state drive supported by the motherboard. If it is a new computer, you can choose NVMe M.2 SSD with PCIe 3.0 or PCIe 4.0 protocol. If it is an old computer upgrade: if the motherboard does not support the M.2 interface, you can choose a SATA solid-state drive; if the motherboard supports the M.2 interface, give priority to the M.2 solid-state drive, after all, the speed and performance of the latter are much stronger than the former.

In NVMe M.2 solid-state drives, there are two types of interface protocols: PCIe 3.0 and PCIe 4.0. The reading speed of PCIe 4.0 is about twice that of PCIe 3.0 and 13 times that of SATA solid-state drives. At present, PCIe 3.0 is the mainstream protocol type in the market, and PCIe 4.0 is a new technology that has just been released, and the price is relatively high. PCIe 3.0 is preferred under a limited budget. The main reasons are as follows:

  1. The reading speed of PCIe 4.0 M.2 SSD is about twice that of PCIe 3.0, and the experience in daily use is not obvious (limited improvement);
  2. PCIe 4.0 M.2 SSDs are expensive, and SSDs with the same capacity are about 1.4 to 2 times that of PCIe 3.0;
  3. PCIe 4.0 M.2 solid-state drives have relatively high requirements for motherboards and CPUs (requires relatively new motherboards), and most old motherboards and CPUs do not support them;

Therefore, if the budget is limited, it is recommended to choose PCIe 3.0 M.2 SSD. If the budget is sufficient and you have extreme requirements for performance, you can directly install motherboards, CPUs, and solid-state drives that support PCIe 4.0, all in one step.

It is recommended to choose a solid-state drive with a SATA interface for upgrading an old computer, because the solid-state drive with a SATA interface uses the same interface as a mechanical hard drive. For new computers, it is recommended to directly choose the SSD with M.2 interface instead of the SSD with SATA interface, because:

  1. SSD with M.2 interface is higher in speed and performance than SSD with SATA interface;
  2. The M.2 interface can be directly plugged into the motherboard, while the SATA interface requires a hard disk cable to connect to the motherboard (additional power supply is required). M.2 saves more space in the chassis;
  3. The price of an entry-level SSD with an M.2 interface is not much different from that of a SATA interface with the same capacity, but the speed is much faster;


In short, when the motherboard supports the M.2 interface, M.2 will always be given priority. If you don’t know which interface your motherboard supports, you can check the brand and model of the motherboard first, and then visit the official website of the motherboard to find out. If you really can’t find the model, you can open the case by yourself and see if there is an M.2 slot on the motherboard, which is usually between the CPU heat sink and the graphics card. Motherboards without M.2 slots can only support solid-state drives with SATA interfaces.

Check the capacity of the solid state drive

At present, the capacities of solid-state drives are 256GB, 512GB, 1TB, and 2TB. Generally, solid-state drives of the same brand and model have higher capacities and higher prices. Now the mainstream capacity in the market is generally 512GB and 1TB. This depends on the specific purpose and budget of the solid-state drive you buy: if the solid-state drive is bought to store massive pictures and videos (even video rendering), it is recommended to choose at least 1TB or more. If For daily office use, 512GB is enough.

Check NAND particles and master control

NAND particles are a kind of semiconductor storage particles, which can be regarded as integrated circuits composed of many capacitors. The data of the solid state drive is all stored in NAND, which is the storage medium of the solid state drive. 80% of the cost of solid-state drives is concentrated on NAND. NAND not only determines the service life of solid-state drives, but also has a great impact on the performance of solid-state drives. The NAND particles of SSDs on the market are mainly divided into the following categories:

  1. SLC (Single-Level Cell, single layer): the best, generally for military or commercial use, and not available on the market. A Cell (capacitor) stores 1 bit.
  2. MLC (Multi-Level-Cell, double-layer): Second only to SLC, it is widely used by general enterprises or those with special needs, and the price is very high. A Cell stores 2 bits.
  3. TLC (Triple-Level-Cell, three layers): the current mainstream. A Cell stores 3 bits.
  4. QLC (Quali-Level-Cell): Starting at the end of 2018, a Cell stores 4 bits. QLC adds storage density, which further reduces costs compared to TLC, but its lifespan and performance are relatively poor. NAND manufacturers currently position QLC as an all-round replacement for solid-state drives with SATA interfaces.

SLC can clearly judge whether a cell is 0 or 1; but MLC is not easy to judge, because different amounts of charge represent different data, and a slight loss of charge will cause errors; TLC has a greater probability of error; Not to mention QLC. Therefore, from the perspective of stability, SLC > MLC > TLC > QLC; from the perspective of service life, SLC > MLC > TLC > QLC, SLC is the most resistant to charge and discharge; from the perspective of charge and discharge speed, SLC > MLC > TLC > QLC, SLC is the easiest to charge and discharge with the fastest speed.

How to choose SSD?

In short, TLC is generally enough, and those who pursue the ultimate cost performance can consider QLC. Currently, manufacturers of NAND particles include Samsung, Toshiba, and Micron.

How to choose  SSD?

As the brain of the SSD, the SSD master is responsible for command, calculation and collaboration, such as allocating NAND data and loads to ensure stable data transmission. In addition, the main control is also responsible for data exchange with the outside, sending various special instruction packets, and processing of particle wear balance. At present, the main control manufacturers include Samsung and Marvell.

Check the random read and write performance IOPS

IOPS (Input/Output Operations Per Second), refers to the number of I/O requests (reading and writing times) that the hard disk can handle per unit time. In testing hard disk random read performance, most software will use 4KB data blocks as the test benchmark, so it is also called 4K IOPS (4K random read and write), and the larger the value, the better (faster).

  1. Applications with frequent random read and write (IOPS), such as small file storage and mail servers, focus on random read and write performance, and IOPS is a key measurement indicator.
  2. For applications with frequent sequential read and write (data throughput), transfer a large amount of continuous data and transfer large files, such as video-on-demand and tens of gigabytes of game files, pay attention to sequential read and write performance.

Pay attention to the difference between random read and write and sequential read and write, please don't be misled by the manufacturer~

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