OVERVIEW

What is SI L1?

Industry-Leading, Low-Latency Coherent Interconnect for Flagship SoCs

SI L1 is a scalable system-on-chip (SoC) fabric that integrates a coherent interconnect, an optional system-level cache, and a configurable non-coherent network-on-chip (NoC) to enable full SoC connectivity for AI-first mobile, laptop, and PC devices.

 

Optimized for SME2 enabled C1 CPU cluster, Mali G1 GPUs, and MMU L1, it serves as the backbone of the Arm Lumex Compute Subsystem (CSS), delivering high compute performance, energy efficiency, and security. The intuitive tooling solution supports seamless interconnect design and optimization for faster system integration and shorter design cycles.

 

FEATURES AND BENEFITS

Integrated Interconnect Innovation, Built for Mobile AI

New Designed Architecture

New interconnect architecture specifically optimized to meet critical power-efficiency, latency, and bandwidth demands of smartphones and laptop devices.

Complete SoC Fabric Solution

Integration of coherent fabric, non-coherent NoC and optional system level cache (SLC) in one fully validated product. Validated with Armv9 CPUs and GPU as part of Arm Lumex CSS Platform.
Extended Battery Life

New short pipeline, together with integrated low latency, ultra-low-leakage system-level cache enable long battery life and Day of Use (DoU) for battery powered devices.

Ready for AI-First Platform

Scalable architecture allows to meet the bandwidth demands of AI use cases like AI agents With support for LPDDR6 bandwidths.

Lowest Latency to Maximize Performance

SI L1 offers industry-leading low CPU-to-DRAM latency. QoS-aware arbitration minimizes dynamic latency in loaded system, and additional low-latency features make SI L1 the ideal interconnect for heterogeneous mobile and large screen compute (LSC) SoCs.

QoS, Coherency & MTE support

Support for interconnect-wide advanced QoS and hardware-managed coherency help meet bandwidth and performance requirements of heterogeneous SoC designs and mobile use cases. Support for Memory Tagging Extension (MTE) significantly enhances the security of the devices.

Key Capabilities

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Performance

75% Interconnect static latency reduction.*

Arm Scalability icon

Area

43% Lower area.*

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Power

86% Logic leakage reduction.*

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SLC

71% RAM leakage reduction.**

*Compared to CI-700 with comparable config on the same process node.*

**Arm POP RAM vs Standard Compiled RAM.**

Arm Interconnect SI L1 Short Block Diagram
SPECIFICATIONS

System Interconnect SI L1 Specifications

SI L1 delivers a fully integrated SoC interconnect solution combining coherent fabric, system cache, and non-coherent NoC, engineered for low-latency, high-efficiency performance across AI-capable mobile and large-screen compute devices.

View Arm Developer for more details.

USE CASES

Designed for the Demands of Intelligent Devices

Smartphones

SI L1 gives smartphones an unparalleled combination of performance, power efficiency, and AI capabilities, essential for next-generation mobile computing experiences. Specifically designed to meet the demanding requirements of flagship smartphones, the technology enables highly responsive AI-driven user interactions, immersive gaming, and superior multimedia performance.

Learn More

Laptops

SI L1 interconnect technology enables laptops to deliver powerful, energy-efficient, and responsive experiences tailored to demanding AI-driven workloads. Optimized specifically for power-efficiency, latency, and bandwidth demands unique to laptops, this technology provides seamless integration of heterogeneous compute elements including Armv9.3-A CPUs, Mali GPUs, and dedicated AI engines.

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RELATED PRODUCTS

Explore Products and Technologies

Arm Lumex CSS Platform

Arm Lumex CSS

The next-generation Arm client compute platform built for the AI era, integrating powerful CPUs, Mali GPUs, and developer-friendly software to deliver differentiated, energy-efficient experiences across mobile tiers.

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C1-Ultra

C1-Ultra

The flagship Armv9.3-A "big" core in the platform cluster, delivering double-digit instructions-per-cycle (IPC) uplift and SME2 for faster, more efficient on-CPU AI acceleration and gaming performance than the previous generation Arm Cortex-X925.

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C1-Premium

C1-Premium

Our sub-flagship Armv9.3-A big core, optimized for background AI inference and task offload, enabling smarter power use and extended battery life in always-on mobile environments.

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C1-Pro

C1-Pro

Premium-performance mid-tier CPU, featuring the Armv9.3-A architecture with 5x AI uplift and 16% higher performance in gaming, ideal for sustained performance in thermally constrained designs.

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Mali GPUs

Mali G1 GPUs

Mali provides the ultimate user experience for entertainment and visual applications across a wide range of smartphone devices.

Explore Mali G1 GPUs
C1-DynamIQ Shared Unit (C1-DSU)

C1 DynamIQ Shared Unit
(C1-DSU)

Enables seamless integration of C1-Ultra, C1-Pro, and C1-Premium in scalable clusters, managing coherency, memory, and system-level performance across workloads efficiently.

Explore C1-DSU

Talk with an Expert

Still unsure which Lumex Interconnect product is right for your SoC project? Talk to an Arm expert and learn more.

Contact Us