PCIe 4.0 x8 Male to x4 Female Extension Cable

The PCIe 4.0 x8 Male to x4 Female Extension Cable is a high-performance passive interconnect solution engineered for systems requiring adaptive connectivity between different PCIe slot sizes while maintaining PCIe 4.0 compliance and signal integrity. This cable converts a larger PCIe x8 slot interface into a smaller PCIe x4 interface, supporting a data transfer rate of 16.0 GT/s per lane and delivering a total bandwidth of approximately 7.88 GB/s for the x4 configuration . It ensures backward compatibility with PCIe 3.0/2.0/1.0 devices. The cable is constructed with 85-ohm impedance-matched wiring (e.g., 31 AWG low-loss twin-axial cable as referenced in 3M’s Gen 4.0 extender assemblies ) and multi-layer shielding to minimize signal degradation in high-speed applications. The passive design addresses form-factor adaptation needs in space-constrained environments such as test benches, compact workstations, or servers, where flexible card placement is critical without sacrificing electrical performance.

Features

• Form Factor Adaptation: Enables physical and electrical compatibility between PCIe x8 and x4 interfaces, allowing x4 devices (e.g., NVMe SSDs or network controllers) to be installed in x8 slots while operating at x4 lane speeds .
• PCIe 4.0 Compliance: Supports PCIe 4.0 specifications with a data transfer rate of 16.0 GT/s per lane, leveraging 128b/130b encoding for high-efficiency transmission .
• 85-Ohm Impedance Matching: Precisely controlled differential impedance reduces signal reflections and ensures integrity at 16.0 GT/s data rates, critical for PCIe 4.0 applications .
• Enhanced Signal Integrity: Utilizes low-loss twin-axial cables with multi-layer foil and braid shielding to minimize insertion loss, crosstalk, and electromagnetic interference (EMI) .
• Passive Design: Requires no external power or active components, relying on high-quality copper conductors (e.g. ) and robust construction for plug-and-play operation.
• Durable Construction: Incorporates gold-plated contacts (e.g., min. 0.76µm thickness ) and reinforced housings to withstand mechanical stress in commercial or industrial environments.

Specifications

• Product Model: PCIe 4.0 x8 Male to x4 Female Extension Cable
• Connector A: PCIe 4.0 x8, Male, Edge Connector
• Connector B: PCIe 4.0 x4, Female, Receptacle
• Cable Type: Passive Copper Extension Assembly
• Pinout Configuration: PCIe-compliant, mapping x8 host interface to x4 device lanes
• Data Rate Support: Up to 16.0 GT/s (PCIe 4.0) 
• Supported Protocols: PCI Express 4.0/3.0/2.0/1.0
• Impedance: 85 ohms differential (compliant with PCIe 4.0 standards )
• Wire Gauge: 31 AWG (high-precision copper, typical for low-loss applications )
• Shielding: Foil and braid for comprehensive EMI protection 
• Cable Length: Standard options: 0.25m, 0.5m (custom lengths up to 1.0m available; longer lengths require validation )
• Operating Temperature: -40°C to +85°C (industrial grade )
• Durability: Minimum 500 insertion cycles
• Safety Standards: RoHS compliant 

Applications

• High-Density Servers: Deploying in rack-mounted systems (e.g., 1U/2U configurations) where x4 add-on cards (e.g., NICs or accelerators) need installation in x8 slots for space optimization .
• Test and Development Benches: Facilitating hardware validation and signal integrity analysis of x4 devices in multi-slot environments, enabling debugging or compatibility testing .
• Compact Workstations: Enabling flexible component placement in small-form-factor builds where motherboard x4 slots are obstructed by larger components like GPUs or cooling systems.
• Industrial and Embedded Systems: Supporting PCIe expansion in ruggedized equipment where reliable high-speed connections and form-factor adaptability are essential .