SanDisk and SK hynix join forces to standardize High Bandwidth Flash memory, a NAND-based alternative to HBM for AI GPUs — Move could enable 8-16x higher capacity compared to DRAM

SanDisk and SK hynix have just signed a memorandum of understanding to collaborate on what could become a pivotal advancement in AI memory infrastructure. Announced in a press release, this agreement aims to standardize “High Bandwidth Flash” (HBF), a NAND flash-based memory technology built into HBM-like packages. This marks the first serious industry push to fuse flash and DRAM-like bandwidth into a single stack, potentially transforming how AI models access and process data at scale.

Unlike traditional HBM, which relies exclusively on DRAM, HBF substitutes parts of the memory stack with NAND flash—trading raw latency for significantly higher capacity and non-volatility. The approach allows HBF to deliver up to 8–16x the capacity of DRAM-based HBM, at comparable costs, while still targeting similar bandwidth levels. Unlike DRAM, which requires constant power to retain data, NAND is non-volatile, enabling persistent storage with reduced energy demands.

That distinction is critical as AI inference scales out to more energy-constrained deployments. Hyperscalers (companies with massive cloud infrastructure for rent) are now pushing inference to the edge, and cooling budgets in AI data centers are already hitting practical limits.

A couple of years ago, a widely-discussed research paper titled “LLM in a Flash” proposed an architecture where large language models could be efficiently run by using SSDs as an additional memory tier, offloading some of the memory pressure from DRAM. Therefore, by marrying NAND flash’s high capacity with interface designs inspired by HBM’s bandwidth capabilities, SanDisk and SK hynix are effectively proposing a new memory class — one that could support large model inference without incurring the thermal and cost overheads of traditional HBM stacks.

The move is also aligned with broader industry shifts. Samsung, for instance, recently unveiled its own flash-backed AI storage tier dubbed “PBSSD” and is actively working on next-gen HBM4 DRAM expected to include logic die integration and potentially hybrid stacks. Meanwhile, Nvidia's roadmap through its Rubin and Vera GPUs continues to rely heavily on HBM, and integrating flash may offer a path to scale memory without linearly scaling cost and power. You can see our deep-dive into HBM roadmaps for Samsung, Micron, SK hynix to learn more.

SanDisk’s HBF prototype, shown at the Flash Memory Summit 2025, was developed using its proprietary BiCS NAND and CBA wafer bonding technologies. The company received the “Most Innovative Technology” award at the event, and announced the formation of a Technical Advisory Board to guide HBF’s development and ecosystem strategy. The board includes figures from both inside and outside SanDisk, underscoring the company's intent to establish HBF as a cross-industry standard, not just a proprietary product.

Sample HBF modules are expected in the second half of 2026, with the first AI inference hardware integrating the tech anticipated in early 2027. While no specific devices or partners have been named, industry watchers speculate that SK hynix's close relationship with Nvidia and other AI chipmakers could accelerate adoption once standards are in place. Previously, Raja Koduri, Intel's former graphics chief and now running his own startup, also joined hands with SanDisk to advise on HBF for AI GPUs.

If successful, this collaboration could pave the way for heterogeneous memory stacks where DRAM, flash, and potentially even new persistent memory types coexist within AI accelerators. In doing so, it could also give hyperscalers a much-needed alternative to escalating HBM costs while enabling next-gen models that are increasingly bumping against memory ceilings. After all, SK hynix is already the world's top-selling memory maker, so they stand to gain from any potential substitutes developed in-house.

This is also not uncharted territory for SanDisk as the firm has a long-standing history of collabs and most recently partnered with Kioxia, the inventor of flash, to develop BiCS9 using CMOS processes. Despite the fact that HBF is utilizing CBA-based BiCS NAND, SanDisk did not confirm whether it's the same generation it has worked with Kioxia on. We will update the article if new information surfaces.

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