Glossary
QLC NAND
Quad-Level Cell flash memory — stores 4 bits per cell. Cheapest mainstream NAND, lower endurance and slower sustained writes than TLC.
QLC packs 16 voltage states into a single cell (vs 8 for TLC). The cost per terabyte is the lowest of any modern NAND, which is why high-capacity (4 TB, 8 TB) consumer SSDs often use it.
The trade-off
- Endurance drops to 100–400 P/E cycles. A 1 TB drive may rate only 200–400 TBW.
- Sustained writes after the SLC cache fill collapse to 80–150 MB/s — slower than a hard drive at the extreme.
- Read performance and burst writes remain competitive with TLC.
When QLC is fine
- Cold-storage drives (Steam library, media archive).
- Boot/OS drives — write volume is low.
- Capacity-first builds where 4 TB TLC is out of budget.
When to avoid
Video editing scratch disks, database servers, anything writing 100+ GB per day. The drive will wear, and sustained writes will be painfully slow.
Where this matters
Categories that use qlc nand
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