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What Are QLC, DRAM Cache and SLC Cache? (Part 1)

This year, the SSD market is experiencing a boom due to the new cryptocurrency, Chia, which has also accelerated the rise of high-capacity SSD. Currently, the largest capacity among released products with SATA interface in the market is around 16TB. So, what is the technology that allows SSDs that were only 512GB~1TB to jump up to 16TB? In addition, what are the DRAM Cache and SLC that we often hear about? What practical help can they bring to SSDs? Today we will provide you with an in-depth analysis of these SSD technologies in the hope that it will help you to have a clearer understanding when choosing an SSD, and you will be confused by the various terms again.

 

QLC

The full name is Quad-Level Cells, which is a NAND flash memory that can store 4 bits per cell. Since each cell has its standard size, the more number of transistors is multiplied, the more memory capacity can be provided with the same number of memory cells compared to SLC, MLC, and TLC. Let's put it in a simpler way, the concept of "density" that we learned when we were kids. The more children that can put inside the same classroom, the more people will be taught at the same time.

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However, QLC requires to control more sets of voltages at the same time and the writing mechanism will be more complicated, which has its own limitations in terms of reliability and lifetime. To continue with the previous example, teaching more children at once makes teaching more difficult and also makes it more difficult to grasp the learning and memory progress of each child. That is why there have been doubts and challenges about durability when QLC products first came out to the market in 2018.

 

But!!! That's just an inherent limitation, we can improve the children's learning and memory progress by improving the teacher's education methods, adding new teaching equipment, etc. With QLC's newer manufacturing process and a more powerful chip stacking technology, you will find that the recently released QLC SSDs are actually very close to TLC SSDs in terms of read/write performance and durability. There's no need to worry about durability issues in the past.

 

With technological advances and increased density, the capacity of SSDs has jumped to a new level. A single flash IC can achieve 1TB, and with a total of 16 flash ICs, an amazing 15.3TB QX SSD is born. TEAMGROUP has also released a QX 2.5" SATA SSD with a large capacity of 15.3TB. 8TB and 4TB products will be released as well, so you can look forward to it.
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We will explain the differences between DRAM Cache and SLC SSD in the next article. Stay tuned!

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