The SSDs we use use NAND Flash as the storage medium. As the storage density continues to increase, the cost becomes more and more sensitive. Because the cost of flash memory depends on the chip area, it can be stored in the same area. With more data, Flash will be more cost effective.
Therefore, with the development of technology, there are Single Level Cell (SLC), Multi Level Cell (MLC) and Triple Level Cell (TLC), and there is also a QLC that has not been widely popularized.
Some small partners may not understand the relationship between them. In SLC flash, each storage unit stores only one bit of information, which makes reading cells faster, but its unit cost is higher; MLC flash stores two storage units per memory unit. Bit information, read speed and lifetime are lower than SLC, but the price is also 2 to 4 times cheaper; TLC Flash stores 3 bits of information per memory unit, the advantage is that the cost is much lower than SLC or MLC flash, more suitable For consumer applications, to QLC Flash, each memory cell can store 4 bits of information to store more information, and the lifetime will be lower than TLC.
After QLC, in fact, 5bit MLC flash memory has been under study, referred to as PLC, it has to control 32 different voltages, which is more complicated, but at the just-opened 2019 FMS International Flash Conference, it has begun to explore PLC flash memory. Probably, it has been put on the agenda. Although there is no concrete object, it is believed that with the wide-scale popularization of QLC, the speed of PLC research and development will be further accelerated.