Sandisk reveals mammoth 256TB SSD, introduced with cutting-edge UltraQLC flash memory - high-end SSDs for massive storage capacity in the enterprise sector are additionally available in 128TB.
SanDisk, a leading manufacturer of storage solutions, has announced the launch of a new solid-state drive (SSD) - the UltraQLC 256TB NVMe SSD. This high-capacity drive is designed for high storage density applications, particularly in the hyperscale cloud and AI workloads where large datasets are written over extended periods.
The UltraQLC 256TB SSD is based on Sandisk's enterprise-grade UltraQLC platform, which is specifically designed for drives that offer high capacity, high performance, and high reliability. The new SSD utilizes a custom multi-core controller, custom firmware, and 2Tb BiCS8 3D QLC NAND memory.
However, it's important to note that the UltraQLC 256TB SSD does not use pseudo-SLC caching, which affects its performance. Compared to pseudo-SLC-cached SSDs, the UltraQLC SSD has slower write latency and throughput. The native QLC programming latency (~800–1200 µs) is about three to five times higher than pseudo-SLC cached NAND (~200–300 µs), leading to lower short burst and sustained sequential write speeds on UltraQLC compared to pseudo-SLC-cached drives.
To mitigate these inherent QLC performance limitations, Sandisk has implemented several strategies. The drive supports power-loss safe writes on the first pass without an SLC cache, thanks to its Direct Write QLC Technology. Additionally, it uses a substantial DRAM cache and intelligent data mapping to optimize write performance and endurance. The controller and NAND design leverage parallelism across memory planes and dies to improve throughput despite slower single-cell programming times. Extra capacity is reserved for background maintenance and wear leveling, boosting consistent write performance and endurance. Adaptive Frequency Scaling and Data Retention Profile Optimizations further reduce NAND refresh cycles and manage power and performance to improve energy efficiency and data reliability over time.
Despite its lower write performance and higher latency compared to pseudo-SLC-cached SSDs, the UltraQLC 256TB SSD offers consistent performance without cache bottlenecks. Sandisk positions this drive for workloads that benefit from massive capacity, energy efficiency, improved reliability, and consistent throughput over extended writes rather than peak performance.
The 128TB and 256TB UltraQLC SSDs are scheduled for release in the first half of 2026. Sandisk also announced the SN670 SSD, which also relies on the UltraQLC platform. The UltraQLC 256TB NVMe SSD includes Dynamic Frequency Scaling, which may boost performance by 10% at any given power level. Furthermore, the Data Retention profile can reduce retention-related recycling by up to 33%.
While the UltraQLC 256TB SSD may not be suitable for everyone due to its performance characteristics, it is a strategic solution for hyperscale cloud service providers and enterprises building AI data infrastructure. The consistent performance over long writes, combined with its high capacity and energy efficiency, makes it an attractive option for large AI data sets that require hours to write.
Technology and data-and-cloud-computing sectors will find the SanDisk UltraQLC 256TB NVMe SSD particularly beneficial, given its design for high storage density applications in the hyperscale cloud and AI workloads. Leveraging Sandisk's enterprise-grade UltraQLC platform, this drive offers high capacity, high performance, and high reliability, making it a strategic solution for hyperscale cloud service providers and enterprises building AI data infrastructure.
