SK hynix Begins Mass Production of World’s First 321-Layer QLC NAND Flash

SK hynix has announced that it has successfully begun mass production of its 321-layer QLC NAND Flash solution, marking the first time QLC (Quad-Level Cell) NAND has surpassed the 300-layer threshold. The new 2Tb (terabit) chip doubles the capacity of existing QLC products and introduces 32-die stacking technology, setting the stage for next-generation PC, smartphone, and AI data center storage solutions.

A Leap in Storage Density and Efficiency

The 321-layer QLC NAND achieves its breakthrough by integrating more planes, increasing from four to six independent units per chip, which allows for greater parallelism in read and write operations. This change significantly enhances simultaneous read performance while also mitigating performance degradation typically associated with large-capacity NAND.

Performance improvements compared to previous QLC NAND include:

• 2x faster data transfer speeds

• Up to 56% higher write performance

• 18% faster read performance

• 23% improvement in write power efficiency

This combination of higher density, faster performance, and improved energy efficiency positions the chip as a prime candidate for AI-driven data centers, where low power consumption is crucial.

First Application: PCs, Then Data Centers and Smartphones

SK hynix confirmed that the 321-layer NAND will debut in PC SSDs before expanding to enterprise SSDs (eSSDs) for data centers and UFS storage for smartphones. The company will leverage its 32DP packaging technology, which enables stacking of up to 32 NAND dies in a single package, effectively doubling storage integration density for ultra-high-capacity enterprise SSDs.

“With the start of mass production, we have significantly strengthened our high-capacity product portfolio and secured cost competitiveness,” said Jeong Woopyo, Head of NAND Development at SK hynix. “We will make a major leap forward as a full-stack AI memory provider, in line with the explosive growth in AI demand and high-performance requirements in the data center market.”

Mass production of the 321-layer QLC NAND Flash not only reinforces SK hynix’s position as a memory leader but also underscores the company’s commitment to enabling AI-driven workloads, next-generation PCs, and future smartphones. Customer validation is ongoing, with commercial deployment expected in the first half of 2026.

Do you think QLC NAND is ready to power the next wave of AI-focused SSDs, or will TLC still dominate premium performance markets for now?