Solid state drives buying guide- general principles to avoid be deceived

Source:   Editor: admin Update Time :2019-08-20

There is some people use HDD at present. Solid-state drives can give you more than just a boost in your day job or game. SSDs are definitely revolutionary. It's not just that the boot is fast.

When people face the problem how to improve the slow speed of their antique computer?  They tend to buy a solid state drive or add a memory stick to computers, which will settle down 80% problem in computers especially computers for daily office use. So, the question is how much capacity should we choose when buying SSD? What pitfalls can we avoid when buying SSDs? So let's talk about that.

We know that the mainstream SSD capacity is generally divided into 120G (128G), 240G (250G, 256G), 480G, 500G (512G), up to 720G, 1T, 2T. In addition to capacity, NAND flash types also need to be noticed, because they are core particles, which are related to product cost, lifespan and speed. It will confuse green hands to understand what is SLC, MLC, TLC and so on. So what popular methods can make green hands clear to avoid those pitfalls?

Bigger capacity is not always better in the same level SSD
Many rich friends tend to choose larger capacity SSD among similar SSD. It is no problem in fact, but redundancy need to be noticed in SSDs with the same capacity.
Because flash memory has a read-write life, data are prone to produce errors after SSDs using long time. In order to ensure data security, many manufacturers will leave a certain amount of empty redundant space when producing SSDs so that data can be read and written normally in case of errors occurring in SSDs. These redundant spaces, which are not available at ordinary times, can save data at critical times. Therefore, "redundancy" is a factor worth considering when SSD capacity is same. The greater the redundancy is, the more fault tolerant SSD is, which leads to data more secure.

Flash memory differs greatly in lifespan and speed
Flash memory chip is the storage medium of SSD and the guarantee of SSD high-speed of read and write. Owing to flash memory has a lifetime, there's also a difference in speed. Different types of flash memory have different lifespan and speed. The main flash memory on the market is divided into SLC, MLC and TLC
SLC has the best performance and service life, but is the most expensive.
MLC has middling performance in all aspects and lifespan, the price is higher. 
TLC has slower speed, shorter lifespan and cheapest.

In consequence, trying to choose SSDs with MLC NAND flash if you have adequate budget.

The controller is equivalent to the brain of an SSD. The faster the brain works, the better the SSD will perform. There are many factors that determine the performance of the master chip, such as frequency, number of channels, number of cores and architecture and so on. In general, high-end SSD controllers include Samsung MGX and Marvel 88SS9189. Take the latter as an example, it uses dual-core architecture with running frequency of 400MHz and has 8 flash channels and non-compression algorithm. While the lower-end JMicron JMF667H controlled use single-core ARM9 architecture with running frequency of 246 MHZ and the number of flash channels is only four. It is recommended to choose high-end master control chip as far as possible.

When it comes to hard disk interface, we first think of the SATA interface, which is the most mainstream hard disk interface. However, SATA interface are not ideal choose for SSD. Because the SATA interface is a product in the age of Hard Disk Drive, its maximum transmission speed is 600MB/S which can’t bring SSD's superiority into full play.

Currently, faster interfaces include PCI-E and M.2 compared with SATA

M.2 interface is special, because there are actually two types of M.2 interfaces, Socket2 and Socket3. The corresponding physical interface forms of the two are B Key and M Key respectively. Part of M. 2 SSD uses the Socket2 B Key interface, which is still the traditional SATA bus, so the reading and writing speed of this kind of M. 2 SSD is no different from that of ordinary SATA SSD with maximum speed of 600MB/S. The real PCI-E bus is the full - speed Socket3 M Key interface. The full speed of such SSDs can reach 3.2GB/S.

Transport protocol
The main HDD and SATA SSD use AHCI transfer protocol, which works well with SATA interfaces because SATA are inherently limited in speed.
But with the advent of SSD with PCI-E interface, the AHCI transport protocol became a bottleneck. It severely limits the 4K read-write performance of SSDs. In this case, the new NVMe protocol came out which was developed specifically for the new PCI-E SSD. Compared with the traditional AHCI protocol, the delay of NVMe protocol is significantly reduced by 50%. Meanwhile, NVMe protocol supports greater data throughput which is also much faster than AHCI. These two advantages enable SSDS with NVMe protocol faster 4K data read-write performance.

Pay attention to after-sales and brand praise
Due to the low threshold of SSD and the high dependency of SSD quality control on subjective factors, the performance and reliability of SSD are uneven.

Although the quality of SSD can only be experienced through long-term use after purchasing, it can be identified from warranty period. For example, some SSDs with high quality NAND flash, such as those of big brands, have a warranty period of up to 10 years! The warranty period of mainstream brands typically lasts three to five years. Choosing SSDs with five years of warranty if you're a conservative.
In addition, it is essential to pay more attention to the online reputation of SSD brand before buying.

These are minefields easy to tread when buying for SSDs.
In general, manufacturers advertise their SSDs for their speed and capacity. For some sensitive key parameters, they tend to vague or selective neglect. It is easy to step on thunder, even the experienced customers may inevitably roll over. So you must pay attention when choosing SSD!

So we have to be careful when choosing SSDs. After all, data is priceless. As a carrier for storing priceless data, we must above those factors into comprehensive consideration when buying SSDs.


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