SK hynix says it’s going to produce ultra-high-capacity, high-performance SSDs for AI servers by using its 321-layer 3D NAND in QLC format.
SK hynix is beginning mass production of a 321-layer, QLC 2 Tb die, the world’s first implementation of more than 300 layers using QLC technology, with product shipping in the first half of 2026, assuming successful customer validations. The product will have 6 planes, independent operating units of flash, which can operate in parallel and provide more performance than its current 4-plane design. It says this has doubled data transfer speed, write speed has increased up to 56 percent, with read performance going up 18 percent. Write power efficiency is more than 23 percent better.
Jeong Woopyo, Head of NAND Development at SK hynix, stated: “With the start of mass production, we have significantly strengthened our high-capacity product portfolio and secured cost competitiveness. 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.”
This follows recent announcements of a 256 TB Sandisk UltraQLC SN670 SSD and 245.8 TB Kioxia LC9 SSD, both of which use the two joint-venture partner’s 2 Tb QLC (4 bits/cell) die fabricated from 218-layer 3D NAND. Sk hynix subsidiary Solidigm has been leading the development of high-capacity SSDs, pioneering a 61.44 TB QLC drive in July 2023 and a 122 TB drive in November 2024, which used 192-layer QLC 3D NAND. However, Solidigm has remained stuck at the 192-layer level while competitors have ramped up their 3D NAND density beyond 200 layers. Now SK hynix is joining the fray with a 321-layer technology, far denser than Kioxia and Sandisk’s 218-layer technology.
SSD products using SK hynix’ latest tech will be released in two phases, with PC drives first, then enterprise SSDs (eSSDs) and UFS cardlets for smartphones. The AI server eSSDs will have 32 stacked NAND dies in a single package. We can be fairly certain they will match Sandisk and Kioxia capacity levels and could, maybe, exceed them. The drive’s commercial launch is scheduled for the first half of next year following completion of customer validation.
Kioxia LC9 Series SSDs are now sampling with select customers. The Sandisk UltraQLC SN670 drive will ship in the first half of 2026.
With Solidigm still at the 192-layer level it seems clear that it needs a substantial NAND technology makeover up to the 300+ layer count for it to regain its density and capacity effectiveness.
