SFF-8654 to SFF-8654 SlimSAS Cable for PCIe Gen5

📐 Connector Type

• SFF-8654 4i (38-pin): x4 PCIe lanes

• SFF-8654 8i (74-pin): x8 PCIe lanes (or 2 x 4i bifurcation)

• Orientation Options:

• Straight-to-straight

• Straight-to-right-angle

• Right-angle-to-right-angle (as needed for airflow or compact routing)

🚀 PCIe Gen5 Performance Specifications

• Speed:

• Up to 32 GT/s per lane (gigatransfers per second)

• Total bandwidth:

• 4i (x4): ~128 Gbps raw (~126 Gbps usable)

• 8i (x8): ~256 Gbps raw (~252 Gbps usable)

• Protocol: PCI Express Gen5 (compatible with Gen3/Gen4 as well)

• Lane Count: x4 or x8 differential pairs

• Impedance: 85 Ohms differential

• Signal Integrity:

• Must meet PCIe Gen5 loss budgets (typically <28 dB insertion loss for the full path)

• Requires very short, low-loss routing

• Eye mask compliance needed for Gen5 at 32 GT/s

🧵 Cable Construction

• Wire Type: Twinaxial, ultra-low skew

• Gauge: 32 AWG (sometimes 30 AWG for very short runs)

• Length:

• Recommended: ≤ 50 cm (19.7 in)

• Max practical: ~75 cm with excellent shielding and equalization support

• Shielding:

• Individual pair shielding (foil)

• Overall braid or foil wrap

• Grounding to connector shells

⚙️ Use Case

• PCIe Gen5 Internal Interconnect:

• Between PCIe Gen5 host (e.g., CPU, RAID, NIC) and endpoint (e.g., U.2/U.3 NVMe drives, backplanes, GPUs)

• Midplane-to-board or board-to-board in dense server and storage architectures

• Typical Devices:

• SlimSAS-equipped RAID/NVMe controllers

• High-performance compute (HPC) platforms

• Gen5-capable enterprise backplanes or carrier boards

⚠️ Notes

• Cable and connector quality are critical at Gen5 speeds. Use certified high-speed materials and keep lengths as short as possible.

• Backplane routing and retimers may be required for anything >50 cm or high-loss paths.