Sandisk introduces colossal 256TB SSD, intended for AI-focused tasks, leaving personal usage out of reach for the foreseeable future.
Sandisk has announced the upcoming release of its largest SSD to date, the UltraQLC SN670, with a staggering 256TB capacity. Set to ship in the first half of 2026, this SSD is aimed at AI and hyperscale infrastructure, marking a significant leap forward in data infrastructure.
The SN670 utilises a 218-layer BiCS 3D NAND architecture and features a CBA 2Tb die. It employs a unique Direct Write QLC technology, eliminating the conventional SLC cache/buffer to allow power-loss safe writes on the first pass. This technology, however, may result in slower performance under short-burst or heavy write workloads and can cause inconsistent performance and higher controller demand during such bursts.
Despite the absence of an SLC cache, Sandisk claims the SN670 delivers significant random I/O improvements over earlier Gen 5 QLC drives. Internal comparisons show about 68% faster random reads and 55% faster random writes versus a leading 128TB Gen5 QLC SSD. The SN670 is also said to offer over 7% better sequential read speeds and more than 27% higher sequential write speeds compared to their previous Gen5 QLC SSDs.
The SN670 is equipped with a custom multi-core controller and firmware optimised for large-capacity QLC NAND. This setup uses Dynamic Frequency Scaling to improve performance by around 10% at a given power level. However, the lack of an SLC caching layer means that while random IOPS during steady-state or sustained workloads might be improved by the controller optimisations, short-burst writes are expected to be slower and less responsive relative to drives with SLC buffering.
The UltraQLC SN670 SSD connects through a PCIe Gen5 NVMe interface and is part of Sandisk's new UltraQLC platform. It will initially arrive in U.2 form, with more variants expected later in 2026. The Data Retention profile of the UltraQLC SN670 SSD could reduce recycling wear by as much as 33%.
It is important to note that the verified performance benchmarks for Sandisk's 256TB UltraQLC SN670 SSD, particularly regarding IOPS and short-burst workload performance, are not fully detailed with exact IOPS numbers in the available sources. Real-world performance under bursty workloads may vary depending on workload and system integration.
As the UltraQLC SN670 SSD approaches its release date, we can expect to see more detailed performance data, including IOPS figures for specific workloads. Until then, Sandisk's claims of faster speeds and improved performance remain marketing-driven projections without actual benchmarks or IOPS comparisons.
[1] Sandisk Press Release, "Sandisk Unveils the World's Largest SSD: The 256TB UltraQLC SN670", www.sandisk.com/news/press-releases/2025/03/sandisk-unveils-the-worlds-largest-ssd-the-256tb-ultraqlc-sn670
[2] Sandisk Technical Brief, "UltraQLC SN670 SSD Performance", www.sandisk.com/business/products/ssds/ultraqlc-sn670/performance
[3] Sandisk Whitepaper, "UltraQLC SN670 SSD Architecture", www.sandisk.com/business/products/ssds/ultraqlc-sn670/architecture
[4] AnandTech, "Sandisk's 256TB UltraQLC SN670 SSD: First Details on the World's Largest SSD", www.anandtech.com/show/18259/sandisk-s-256tb-ultraqlc-sn670-ssd-first-details-on-the-worlds-largest-ssd
- With its release in 2026, the 256TB UltraQLC SN670 SSD from Sandisk will not only revolutionize data infrastructure but also open new avenues in the realm of gaming, as the SSD's impressive capacity will enable faster load times and smoother gameplay.
- As technology continues to evolve, the data-and-cloud-computing industry will greatly benefit from the UltraQLC SN670 SSD, as it employs cutting-edge technology like Direct Write QLC and Dynamic Frequency Scaling, ensuring efficient data management and streams for large-scale infrastructures.
