NAND memory

     The three main parts of SSD: controller, DDR memory, and flash memory. DDR memory usually present when is a cache which speeds up frequency accessed data. The controller just the main controller between the chip inside and the device where you are adding storage device, but not least is the NAND flash, this is most essential part of the SSD.

    NAND memory is a type of non-volatile storage, which means it is unlike the volatile storage devices, it does not depend on any power to retain data. The entire purpose behind NAND flash devices is not only reduce the cost per bit but also increase maximum chip capacity. This will allow memory to come closer to other storage devices like hard disk drives. NAND uses electrical circuits to store the data as blocks, once the electric circuit is broken and the power is detached. NAND storage continues to retain the data, using semiconductor. Each NAND essentially has two gates control and floating gates. These gates ensure that data flows perfectly and if you want to program one cell, a voltage charge is sent to the control gate, and the electrical charge is stored in the floating gate.

    There are 4 main types: SLC, MCL, TLC, and QLC. The main thing that distinguishes them is how many bits that each cell can store inside. As the name suggests SLC or single level cells store one bit of data per cell. MLC or multi-level cells store two bits of data per cell. The number keeps climbing, and in the case of TLC or triple level cells, we get three bits of data per cell and then in QLC or quadruple level cells, we can get four bits of data per cell. The greater number of bits, the more capacity each cell can hold. This means QLC can hold the maximum level of storage and SLC can hold the least. Unfortunately, the maximum amount of storage comes at a cost, and that is speed and endurance. This means that even though SLC flash can hold the least capacity and it also the fastest, and more precise, and of course, the most expensive. Due to its cost, these chips are mainly used in industrial use, not in the consumer space. On the other hand, MLC is much cheaper than SLC, and it has far greater capacity as well. However, its durability and speeds are not up to SLC’s level. As we keep going up to TLC, and the QLC, the price does get lower but so does the durability and speeds comparatively. This is why TLC and QLC are mainly reserved for consumer level usage while the former 2, the MLC and SLC are mainly used by enterprise. However, TLC SSDs are now being introduced in enterprise. Up until now, we need to talk about how the cells are arranges.

    Originally, memory cells were arranged side by side which was called 2D NAND. Nowadays, we have 3D NAND technology. The memory chips are stacked on top each other. The whole point of this is to make the device run much faster and more efficient while simultaneously holding more information. Here at Sabrent our drives use 3D NAND, 3D NAND has many advantages over the traditional 2D NAND as it has higher density and can be written and raised more times than 2D NAND, because it has larger memory cells while 3D NAND has existed for more than a decade now. It has recently entered the market with some incredible developments as it has been able to provide lower power consumption, better performance and lower cost per bit of storage. As TLC and QLC memory with 3D NAND grows increasingly popular. One cannot help but wonder which is better and what are the pros and cons of each. In some cases, bigger might be better but when comparing QLC and TLC, TLC is able to tolerate a much higher number of write and arrays operations due to its fewer bits written per cell.