OpenSFF Compute Node Specification

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1. Introduction

1.1 Purpose

This document defines the OpenSFF specification for interoperable compute nodes. These standards enable modular, small form factor computing solutions across desktop workstations, all-in-one systems, and data center servers. This specification promotes an ecosystem of compatible components, innovation, and flexible system design.

1.2 Scope

This document defines the mechanical, electrical, and thermal characteristics of OpenSFF compute nodes. It covers the following aspects:

  • Form factor and dimensions
  • Mounting interface
  • Connector placement and specifications (Core connector and Enterprise connector; see Section 2)
  • Electrical power requirements
  • Thermal design considerations for passive cooling
  • Compliance and certification requirements

It applies to compute nodes that support a range of processors, from low-power solutions like the Intel N100 to high-performance APUs like the AMD Strix Halo. It defines requirements for both desktop and server variants of the compute node.

Note: The OpenSFF Enclosure Standards document provides additional specifications for enclosures that house OpenSFF compute nodes, and should be used in conjunction with this document.

1.3 Terminology and Abbreviations

  • 4C+: Protocol-agnostic multi-lane high-speed connector with 168 contacts
  • 4C: Protocol-agnostic multi-lane high-speed connector with 140 contacts
  • APU: Accelerated Processing Unit
  • EMC: Electromagnetic Compatibility
  • EMI: Electromagnetic Interference
  • TDP: Thermal Design Power
  • VRM: Voltage Regulator Module
  • SMT: Surface Mount Technology
  • PCB: Printed Circuit Board
  • DIMM: Dual In-line Memory Module
  • CAMM: Compression Attached Memory Module
  • NVMe: Non-Volatile Memory Express
  • USB: Universal Serial Bus
  • M.2: A form factor for solid-state drives
  • I/O: Input/Output

1.4 Document Conventions

  • All measurements and numeric values shall include their associated units.
  • Requirements: The words "SHALL," "MUST," "SHOULD," and similar terms are used to indicate the relative degree of obligation in accordance with accepted standards practices as described in RFC 2119. See examples:
    • "SHALL" or "MUST" indicate a mandatory requirement.
    • "SHOULD" indicates a recommendation.
    • "MAY" indicates that something is permissible.

1.5 Versioning Guidelines

The full version of any OpenSFF standard MUST follow the format “Year.Major.Minor.STAGE#”. This consists of:

  • Year: The two-digit year in which the specification cycle began (e.g., 26 indicates the 2026 revision cycle). The Year field reflects a new generation of the standard that introduces substantial design or performance changes across the ecosystem.
  • Major: Incremented when a change or clarification may affect product implementation.
  • Minor: Incremented for editorial or non-technical changes that do not affect product implementation, including non-breaking corrections or clarifications made after an official version is released.
  • STAGE#: An optional field that indicates the document’s development status, along with a number denoting revisions within the stage. These stages are:
    • DRAFT#: An internal working draft for development and early review
    • RC#: Release candidate, with completed content and published for public or partner review
    • (no suffix): Final release of a version



2. Compute Node Overview