SK hynix Begins Shipping 321-Layer QLC NAND cSSDs, Dell First Customer

SK hynix has started shipping its PQC21 cSSD, the first product built on its 321-layer QLC NAND flash technology. The product is available in 1 TB and 2 TB capacities, with Dell as the first customer starting this month. QLC (Quad-Level Cell) stores four bits per cell, which maximizes storage density per unit area but has historically come with a write performance penalty compared to TLC (Triple-Level Cell). SK hynix addresses that with SLC caching, frequently accessed data is written to faster SLC-mode regions first before being transferred to the QLC cells, smoothing out the performance gap for typical workloads.

According to market research from IDC (International Data Corporation), the QLC NAND is expected to go from 22% of the global cSSD market in 2025 to 61% by 2027, so the timing of this launch makes sense. SK hynix says it will expand beyond Dell to other major customers as production scales up.

On the broader NAND market, Samsung is still on top with $6.6 billion in revenue, up 10% QoQ, though its share slipped to 28% as bit shipments dropped during a process transition. SK Group (SK hynix and Solidigm combined) had the strongest quarter of the top five, with revenue up 47.8% QoQ to around $5.21 billion and market share climbing to 22.1%, driven by mobile NAND and enterprise SSD demand.