SK Hynix and SanDisk launched HBF, a new memory technology bridging HBM and SSD storage, at the FMS 2026 conference.
On August 4, during the FMS 2026 conference in California, SK Hynix and SanDisk unveiled the specifications for HBF, a new intermediary memory technology designed to bridge high-speed HBM memory and SSD storage.
Key features of HBF include:
- Up to 512 GB capacity, utilizing 8 or 16 NAND chips;
- Bandwidth between 0.4 TB/s and 3.0 TB/s;
- UCIe connection interface, promoting compatibility with various CPUs and GPUs.
This announcement positions HBF as an open standard, shared through the Open Compute Project, rather than a proprietary technology.
With the introduction of HBF, modern AI server architectures are expected to adopt a four-tier memory hierarchy:
- HBM for processing high-speed, critical data directly in the core (highest speed, limited capacity, high cost).
- CXL for reducing latency in traditional RAM while ensuring CPU/GPU compatibility.
- HBF to connect RAM and SSD, achieving HBM-like speeds with greater capacity through cost-efficient NAND.
- NVMe SSD for storing less frequently accessed "cold" data.
In the context of large language model infrastructure, managing extensive contexts and model weights during inference poses challenges:
- CXL caters to data needing quick access and frequent updates with ultra-low latency;
- HBF is tasked with holding large context caches and AI model weights that surpass the limits of HBM and CXL.
The collaboration for HBF standardization between SK Hynix and SanDisk began in August 2025, with a consortium formed in February 2026 that also includes Google and Tenstorrent.
Additionally, at the FMS 2026 event, SK Hynix showcased its development of 375-layer 4D NAND (V10), claiming a 2.5 times increase in memory performance per watt compared to previous generations, with mass production of eSSD set for early next year.
As reported by Yahoo Finance, SK Hynix's stock has jumped over 330% since the start of 2026, despite losing nearly half its value since June's peak.
