- Sandisk’s 256TB SSD skips cache completely, elevating issues about short-burst workload efficiency
- Claims of quicker speeds stay unverified with out public benchmarks or IOPS efficiency numbers
- Direct Write QLC might sacrifice velocity in change for larger reliability and knowledge integrity
Sandisk has introduced a 256TB SSD, the UltraQLC SN670, which is about to ship within the first half of 2026.
This mannequin represents the most important SSD ever revealed by the corporate, marking a daring step towards high-density storage options tailor-made for AI and hyperscale infrastructure.
Though the corporate plans to launch the 128TB model to testers inside weeks, full business availability stays months away.
An structure constructed for scale, not velocity
At its core, the SN670 is constructed on a 218-layer BiCS 3D NAND structure and contains a CBA (CMOS straight Bonded to Array) 2Tb die.
It connects via a PCIe Gen5 NVMe interface and is a part of Sandisk’s new UltraQLC platform.
Not like standard SSDs that buffer knowledge via pseudo-SLC caches, this mannequin makes use of a “Direct Write QLC” method.
This simplifies the writing course of and makes the drive extra power-loss protected, nevertheless it additionally introduces tradeoffs, particularly relating to efficiency underneath heavy or short-burst masses.
With out an SLC cache, the SN670 might endure from slower short-burst writes, inconsistent efficiency underneath load, and elevated controller calls for, making it much less responsive throughout intensive or unpredictable workloads.
Nevertheless, Sandisk claims the SN670 delivers over 68% quicker random reads and 55% quicker random writes in comparison with a number one 128 TB Gen 5 QLC SSD.
The sequential learn speeds are over 7% higher, whereas sequential write speeds enhance by greater than 27% in inside comparisons.
Sandisk has emphasised advantages like Dynamic Frequency Scaling, which is claimed to enhance efficiency by as much as 10 p.c on the identical energy stage
It additionally claims the Information Retention profile might scale back recycling put on by as a lot as 33%.
Each options are supposed to boost longevity and scale back power consumption.
Nevertheless, none of those claims are backed by disclosed efficiency knowledge comparable to learn/write speeds or endurance figures.
Internally, the UltraQLC SN670 is supported by a customized controller and firmware, which Sandisk says allows higher latency and bandwidth, however with out precise benchmarks or IOPS comparisons, these statements stay marketing-driven projections.
It’s value noting earlier iterations of Sandisk’s enterprise drives utilizing QLC NAND confirmed limitations in comparison with TLC-based fashions.
On this case, native QLC programming latencies might attain 800–1200 microseconds, a number of instances slower than SLC-based designs.
Sandisk could also be counting on optimizations like massive DRAM buffers or superior die parallelism, however such architectural particulars have but to be confirmed.
The ultimate product will arrive in U.2 type initially, with extra variants anticipated later in 2026.
For now, Sandisk’s 256TB drive is a symbolic leap towards future knowledge infrastructure, not a practical choice for mainstream customers.
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