August 26, 2025 /SemiMedia/ — SK hynix said on Friday it has started mass production of a 321-layer 2Tb QLC NAND flash, marking the industry’s first QLC NAND product to surpass 300 layers. The company expects the chip to enter AI data center applications in the first half of next year.

The new product doubles storage density compared with existing offerings by adopting a 2Tb design. To address performance loss that typically comes with higher cell density, SK hynix expanded the internal plane architecture from four to six, boosting parallel processing and overall efficiency.

Performance gains are significant: data transfer speed is twice as fast as the previous generation, write performance is up to 56% higher, read speed improves by 18%, and power efficiency increases by more than 23%. These improvements make the device suitable for power-sensitive, high-performance workloads in AI-driven data centers.

The company said the chip will first be used in PC SSDs, followed by enterprise-grade eSSDs and smartphone UFS products. SK hynix also plans to leverage its 32-die stacking package technology to deliver ultra-high-capacity eSSDs for AI servers.

“By moving this product into volume production, we have reinforced our competitiveness in high-capacity storage and strengthened support for AI and data center demand,” said Jung Yubyo, Executive Vice President at SK hynix. “We aim to advance further as a full-stack AI memory provider.”