SK hynix and SanDisk unveiled the first High Bandwidth Flash (HBF) standard specifications at the opening of Future of Memory and Storage (FMS) 2026, held at the Santa Clara Convention Center in California from Aug. 4–6. The inaugural specification supports capacities of up to 512GB using 8-high and 16-high NAND stack configurations, with three bandwidth tiers (Grade 1–3) delivering roughly 0.4TB/s to 3.0TB/s. SK hynix is rallying major backers including Google DeepMind and Tenstorrent to accelerate adoption of an open HBF ecosystem. The specification, disclosed through the Open Compute Project (OCP), adopts the industry-standard UCIe interconnect, enabling HBF to integrate with GPUs and CPUs, and defines interface, electrical characteristics, die-stacking reliability, packaging guidelines, and software I/O requirements. Unlike HBM, which stacks DRAM dies, HBF stacks NAND flash to deliver a new memory tier between HBM and SSDs. TrendForce views HBF as complementary to HBM, addressing HBM’s high cost and limited capacity, with a likely hybrid memory hierarchy combining HBM for ultra-high-speed computation and HBF for high-density data storage. SanDisk aims to introduce HBF prototypes in the second half of this year, with Japan emerging as a leading production site candidate; a pilot production line is expected to be completed in the second