SK Hynix and SanDisk reveal first specs for High Bandwidth Flash — but don't get too excited, you probably won't be able to buy it anytime soon
A very fast solution, but only on paper for now
by https://www.techradar.com/uk/author/rahim-amir · TechRadarNews By Rahim Amir Published 6 August 2026
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- The first HBF specification defines stacks of up to 512GB with three bandwidth grades from roughly 0.4TB/s to 3.0TB/s, connected to processors over UCIe and published openly through the Open Compute Project
- Google and Tenstorrent have joined the consortium, but Nvidia is not among the named participants, which matters more to HBF's prospects as a de facto alternative to increasingly pricey HBM
- Samples of the first AI inference devices built with HBF are expected to show up in early 2027
SK Hynix and SanDisk have published the first technical specification for High Bandwidth Flash.
Released through the Open Compute Project to coincide with the opening of the Future of Memory and Storage conference, it makes for an impressively fast milestone, arriving six months after the HBF workstream was convened at SanDisk's Milpitas headquarters and a year after the two companies first agreed to standardize the technology.
The solution, at least for now, exists only on paper, and has managed to draw two crucial partners to its consortium: Google and Tenstorrent.
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A promising standard, that focuses on capacity over raw speed
High Bandwidth Flash's specification defines capacities up to 512GB across two stack configurations, 8-high and 16-high NAND dies, and sorts performance into three grades running from roughly 0.4TB/s to 3.0TB/s.
HBF's pitch, unlike its competition, focuses on capacity rather than raw speed. A 512GB HBF stack sits against roughly 48GB to 64GB for an HBM4 stack, which is between eight and ten times the capacity, while the top HBF grade's 3.0TB/s lands inside the 2.0 to 3.3TB/s band typical of HBM4.
It also adopts UCIe, the open chiplet interconnect standard, as the link between an HBF stack and a host processor, enabling the technology to be attached to GPUs and CPUs from different vendors.
What could be challenging is delivering on its promise within a reasonable time; however, SanDisk has been working to a public roadmap since August 2025: first samples of the memory itself in the second half of 2026, and samples of the first AI inference devices built with HBF in early 2027. Neither company updated that schedule with this week's announcement.
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