Lenovo 4XH7A83842 SR635 V3/SR645 V3 X16 PCIE GEN5 Riser 1

Lenovo 4XH7A83842 PCIe Gen5 x16 Riser 1 for SR635 V3 / SR645 V3

Overview

The Lenovo 4XH7A83842 is a PCIe Gen5 x16 Riser 1 expansion module designed specifically for the ThinkSystem SR635 V3 and SR645 V3 server platforms. If your deployment calls for adding a high-bandwidth GPU, NVMe HBA, or multi-port network adapter to one of these AMD-based rack servers, this riser card is the mechanical and electrical interface that makes it possible — translating the x16 Gen5 slot on the motherboard into an accessible, cable-managed riser position inside the chassis. Gen5 PCIe doubles the per-lane bandwidth of Gen4, which matters when pairing high-throughput accelerators or storage controllers where the bus can become the bottleneck. Without the correct riser, those expansion slots remain inaccessible regardless of what add-in card you source.

Compatibility

The 4XH7A83842 is qualified for the following Lenovo ThinkSystem server platforms:

• ThinkSystem SR635 V3 — AMD EPYC 9004-series 1U/2U rack server
• ThinkSystem SR645 V3 — AMD EPYC 9004-series 2-socket 2U rack server

This riser occupies the Riser 1 position. Verify your chassis bay configuration and existing riser population before ordering — Riser 1 and Riser 2 positions are not interchangeable. Consult the SR635 V3 or SR645 V3 Maintenance Manual to confirm slot mapping for your specific chassis revision. Do not substitute with Gen4 or earlier riser assemblies; the Gen5 electrical specification and physical keying are platform-specific.

Installation Notes

The 4XH7A83842 ships manufactured in Mexico and weighs 10 lb, which is consistent with a riser cage assembly rather than a bare card — handle accordingly during installation to avoid flex stress on the PCIe connector. Follow Lenovo's ESD precautions and torque specifications from the platform Maintenance Manual when seating the riser into the chassis guides and securing the retention bracket. No tools beyond a standard #2 Phillips driver are typically required for riser swap procedures on this server family, but confirm with the platform service guide for your specific chassis revision.