In our lab, we mapped the differential pairs for PCIe Lane 0 (connected to the primary x16 slot). Unlike Intel, AMD routes the critical REFCLK (Reference Clock) pins via pins J21 and K23.
After straightening, compare the pin height to its neighbor. For example, pin A1 (VSS) should be exactly level with pin A2 (VDDCR_SOC). A height difference of 0.5mm will cause no contact. am4 pinout diagram exclusive
| Pin Cluster | Pin Range | Signal Type | Critical Function | | :--- | :--- | :--- | :--- | | | A4-B7, Y26-AA30 | VDDCR_CPU | 1.2V – 1.5V Core voltage (Ryzen 9/7/5/3) | | SOC Power | G3-H8, T25-V28 | VDDCR_SOC | 1.05V – 1.2V for Infinity Fabric & iGPU | | Ground | D1-E4, P30-R32 | VSS | Return current path (Crucial for stability) | | PCIe x16 Gen4 | C12-C18, J20-K25 | TX/RX Lanes | GPU connection (Lane 0 to Lane 15) | | DDR4 Memory | L1-M10, N22-P24 | DQ, DQS, CA | Dual-channel DDR4 (2 DIMMs per channel) | | SMU / Control | A30-B32 | SVI2, PROCHOT | Voltage regulation & thermal throttling | | USB 3.2 Gen2 | E26-F28 | SSRX, SSTX | Rear panel Type-A & Type-C | | SATA / NVMe | U2-V8 | PCIe_aux | M.2 SSD or SATA express | In our lab, we mapped the differential pairs