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Ucie Spec _best_ May 2026

1. Executive Summary UCIe (Universal Chiplet Interconnect Express) is an open industry standard for die-to-die (D2D) interconnect and serial bus. It defines the physical layer, protocol stack, and compliance rules to enable heterogeneous chiplets (from different vendors, fabs, and process nodes) to interoperate seamlessly within a single advanced package.

| Protocol | Use Case | |----------|-----------| | | Legacy I/O, GPUs, accelerators, SSDs | | CXL (v2.0/v3.0) | Cache-coherent memory expansion, memory pooling, accelerators | | Streaming | Raw data streams, non-coherent custom IP, streaming interfaces | ucie spec

As Moore’s Law slows, chiplet-based disaggregated System-on-Chips (SoCs) offer the path to higher performance, yield, and reusability. UCIe provides the "glue" to mix compute, memory, I/O, and analog chiplets from multiple sources. | Protocol | Use Case | |----------|-----------| |

UCIe 2.0 (released August 2024, backward compatible with 1.0/1.1). This guide covers both. This guide covers both

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1. Executive Summary UCIe (Universal Chiplet Interconnect Express) is an open industry standard for die-to-die (D2D) interconnect and serial bus. It defines the physical layer, protocol stack, and compliance rules to enable heterogeneous chiplets (from different vendors, fabs, and process nodes) to interoperate seamlessly within a single advanced package.

| Protocol | Use Case | |----------|-----------| | | Legacy I/O, GPUs, accelerators, SSDs | | CXL (v2.0/v3.0) | Cache-coherent memory expansion, memory pooling, accelerators | | Streaming | Raw data streams, non-coherent custom IP, streaming interfaces |

As Moore’s Law slows, chiplet-based disaggregated System-on-Chips (SoCs) offer the path to higher performance, yield, and reusability. UCIe provides the "glue" to mix compute, memory, I/O, and analog chiplets from multiple sources.

UCIe 2.0 (released August 2024, backward compatible with 1.0/1.1). This guide covers both.