QLC (Quad-Level Cell)
STORAGE
Server
Technology
7/8/2025
STORAGE
Server
Technology
QLC (Quad-Level Cell) is a type of NAND flash memory used in Solid State Drives (SSDs) in which each memory cell is capable of storing 4 bits of information, i.e. 16 different levels of charge. This allows for a significant increase in storage density and capacity compared to single-level cell (SLC), dual-level cell (MLC) and tri-level cell (TLC) drives.
Key features of QLC:
- Capacity: high, due to four bits per cell.
- Cost: low cost to store 1GB of data among NAND memory types, making QLC SSDs an economical choice for large volumes.
- Performance: lower than SLC, MLC and TLC, especially noticeable when writing large amounts of data when the cache is depleted.
- Durability: Relatively low at around 1,000-2,000 write cycles, which is less than other memory types.
- Applications: Suitable for budget SSDs with large capacities where price and capacity are more important than maximum speed and capacity.
In summary, QLC is a flash memory technology focused on increasing capacity and lowering the cost of SSDs, but with compromises in speed and durability.