SanDisk introduced a 256 TB SSD.

      SanDisk has announced the release of the 256 TB UltraQLC SN670 solid-state drive, designed for handling resource-intensive artificial intelligence tasks. The new product, unveiled at the Flash Memory Summit 2025, will go on sale in the first half of 2026.

      The new drive uses 218-layer BiCS 3D NAND with CBA technology (CMOS directly Bonded to ) and two-terabit dies. A PCIe Gen5 NVMe interface provides high throughput, making it suitable for big data processing, dataset preparation, and AI storage workloads. According to SanDisk, the SN670’s capacity exceeds the comparable Kioxia LC9 (245.76 TB) by more than 10 TB.

      The SN670 features a specialized controller and a number of optimizations, including Direct Write QLC technology, which protects data on power loss already at the first stage of a write. Unlike many competitors, it does not use an SLC (single-level cell)-based cache, which may affect speed; however, the developers claim a dynamic frequency scaling that increases performance by 10% at a given power level.

      One of the key innovations is a data-retention forecasting system that reduces the need to rewrite data by 33%. This not only increases the drive’s reliability but also reduces energy consumption. Mike James, senior director of enterprise SSD architecture at SanDisk, explained that at these capacities traditional NAND maintenance methods become inefficient. The company developed new algorithms that minimize background processes and extend the drive’s lifespan.

      First samples of the SN670 in the U.2 (2.5-inch) form factor will be delivered to test customers in the coming weeks, with mass shipments starting in 2026. Other variants will be introduced later. In its blog, SanDisk also hinted at the possibility of creating SSDs of up to 1 PB in the future.

      Exact read/write speeds and endurance figures have not yet been disclosed, possibly due to ongoing controller development. However, according to presentations from February 2025, the SN670 demonstrates significant performance gains compared with peers: random read speed is 68% higher, write speed is 55% higher, along with improved sequential operation metrics. The initially announced release window (Q3 2025) has been shifted, likely due to the doubling of maximum capacity and additional testing.

      Earlier, in May 2025, SanDisk CEO David Gekler mentioned new 2 TB QLC chips and the Stargate controller, which will be used in drives supporting PCIe Gen6. This suggests that the SN670 will become one of the fastest solutions in its class, outpacing not only PCIe Gen4 models but also competing Gen5 devices from Solidigm and Phison.

      Naturally, a drive with such a record-breaking capacity is causing excitement among scientists, researchers, and businesspeople. However, a final assessment of its capabilities will only be possible after the full technical specifications are released and independent testing is conducted.