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.
How to use QLC NAND in a real comparison
Quad-Level Cell flash memory — stores 4 bits per cell. Cheapest mainstream NAND, lower endurance and slower sustained writes than TLC. In practice, this is most useful as one part of a decision rather than a standalone quality badge. Compare it alongside the workload, room, ecosystem, budget, and ownership constraints that apply to you; the strongest published figure is not automatically the best outcome for every buyer.
What to check next
Open a product page and check the stated value, configuration, price, and related trade-offs before treating this term as decisive. It is especially relevant in .
Avoid the one-number trap
Manufacturers can describe the same capability under different conditions. Compare like-for-like variants, check the unit and test condition where available, and use a head-to-head page to see whether a measurable difference is material for your own use.
vsMars presents structured catalog values to make trade-offs legible. The linked product and spec pages are the right place to inspect the underlying values before buying.