Lekuo PB65MX3 Universal Memory Expansion Controller
The HBF Standard Accelerates Neural Network Performance

Modern machine learning systems are grappling with a fundamental paradox: while they demand massive datasets to manage neural network weights, access to this data must be near-instantaneous. Traditional memory hierarchies frequently become the primary bottleneck, throttling the performance of even the most powerful accelerators. In response to this challenge, SanDisk and SK hynix, in collaboration with the Open Compute Project (OCP) consortium, have introduced the High Bandwidth Flash (HBF) technical specification.
The standard was developed within a dedicated working group, where key roles were played not only by hardware manufacturers but also by the world's largest cloud infrastructure providers. The involvement of Google and Tensorrent in the standardization process allowed the technology to be validated against real-world production workloads, evolving a theoretical concept into a practical tool for designing data inference systems.
At its technical core, HBF establishes a unified framework for interaction between compute cores and storage. The specification details the xPU-HBF interface, which acts as a high-speed bridge between the accelerator and memory to minimize packet latency. Beyond electrical characteristics and system interfaces, the standard regulates memory stack packaging and reliability requirements—factors critical for densely packed server racks where thermal management and signal integrity dictate overall system efficiency.
A pivotal aspect of HBF is the optimization of the software stack. The specification provides comprehensive guidelines for read/write operation development, enabling engineers at the driver and library levels to manage data streams more effectively and eliminate compute idling. This transforms flash memory from a passive repository into an active element of the data processing pipeline.
Publishing the specification through the Open Compute Project underscores a strategic maneuver by its architects. An open standard prevents vendor lock-in and fosters a broad ecosystem of compatible devices. By establishing a common set of rules, SanDisk and SK hynix aim to position HBF as the industry benchmark for AI storage systems, striking the critical balance between high write density, energy efficiency, and access speeds required for the next generation of intelligent services.

