Quad-level cell (QLC)
NAND flash that stores four bits per cell using sixteen charge levels, optimizing cost per GB over endurance.
Quad-Level Cell NAND stores four bits per cell (sixteen voltage levels), maximizing die capacity at the expense of tighter analog margins, slower program, and lower native endurance than TLC. Controllers rely heavily on SLC caching, large over-provisioning, and host workloads that are read-heavy or sequential. QLC appears in capacity-oriented client SSDs and some denser datacenter/value tiers—not as the default for write-intensive journals or high DWPD enterprise classes. Treat QLC as a media density choice; interface (NVMe/SATA) and PLP features are orthogonal. Quote TBW/DWPD only from the rated SKU.
Relations
- related
- tlc, enterprise-ssd, ftl, write-amplification
- supersedes
- tlc
Advantages
- Highest consumer and nearline capacity per die among planar/3D NAND tiers.
Limitations
- Lower endurance and more complex read margins than TLC or MLC.