High Bandwidth Flash (HBF) Specification: SK Hynix and Sandisk FMS 2026 Announcement

Standard Specifications Released at FMS 2026

On August 4, 2026, at the Future of Memory and Storage (FMS) conference in Santa Clara, SK hynix and Sandisk published the first official HBF technical specification through the Open Compute Project (OCP) . Key highlights:

• The specification is open and royalty-free to drive broad industry adoption .
• It builds on the HBF consortium workstream that began in February 2026, itself following an MOU signed in August 2025 .

Technical Details

Stack Configurations and Capacity

• NAND stacks: 8-high and 16-high configurations .
• Maximum capacity per module: up to 512 GB .
• First-generation modules (Sandisk) use a 16-high stack .

Bandwidth Grades

The spec defines three performance grades :

Sandisk has stated its first-generation HBF will target read bandwidth up to 1.6 TB/s, roughly equivalent to one HBM4 stack but at approximately 10x the capacity .

Interconnect

• The standard uses a parallel, high-speed memory bus directly connected to the GPU/accelerator, similar to the HBM interface, rather than a PCIe/NVMe storage protocol .
• Physical and electrical specifications are published under the OCP open hardware framework .

Consortium and Industry Partners

The HBF consortium is led by SK hynix and Sandisk. Two major industry players have publicly joined:

• Google — joined to support the ecosystem .
• Tenstorrent — the AI chip startup also joined the alliance during the standardization process .

Additional participants have not been officially named, but Samsung is reported to be developing its own HBF technology (see competitive landscape).

Commercialization Timeline

• HBF memory samples: expected in the second half of 2026 from Sandisk .
• First AI inference devices using HBF: expected to begin sampling in early 2027 .
• Mass production target: SanDisk is planning a pilot production line by H2 2026, with volume production in 2027 .
• The FMS announcement did not update the product schedule; these timelines remain from prior company guidance .

Competitive Landscape

The HBF space is emerging, with three distinct approaches:

Key differences between the approaches

• Architecture gap: HBF (SK hynix/Sandisk and Samsung) connects NAND directly to the GPU memory bus via TSV stacking — achieving 1.6+ TB/s bandwidth, rivaling HBM. Kioxia's approach keeps the NAND on PCIe, yielding ~64 GB/s bandwidth — far lower, but with higher capacity per module (5 TB) and much simpler integration .
• Open vs. proprietary: The SK hynix/Sandisk spec is open via OCP. Samsung and Kioxia are pursuing proprietary designs.
• Timing: The consortium is approximately 12–18 months ahead of Samsung's publicly stated timeline; Kioxia's GP Series SSDs are closer to production but serve a different performance tier.