Corner with triangle marker (missing pin) is key. Row A: A1 (VDD18) A2 (VDD) A3 (VDD) A4 (VSS) ... Row B: B1 (VDD18) B2 (VDD) B3 (VSS) B4 (VSS) ... Row C: C1 (PWR_OK) C2 (VDD) C3 (VDD) C4 (VSS) ... ... | Feature | AM4 (PGA) | AM5 (LGA) | |---------|-----------|-----------| | Pins on | CPU | Motherboard | | Pin count | 1331 | 1718 | | DDR type | DDR4 | DDR5 | | PCIe | 3.0/4.0 (CPU dependent) | 5.0 |
Do not confuse AM4 pinout with AM5 – they are mechanically and electrically incompatible. If you need a (e.g., “What pin is VDD_SOC on AM4?”), please provide the motherboard or CPU model, as actual routing varies. For most repair or modding purposes, board-level schematics are required. am4 pinout
| Signal | Description | |--------|-------------| | DQ[0..63] | Data lines | | DQS[0..7]_P/N | Data strobe (differential) | | CA[0..9] | Command/address | | CS#[0..3] | Chip select | | CKE[0..1] | Clock enable | | VDD_MEM | DRAM power (1.2V) | | VPP | DRAM programming voltage (2.5V) | AM4 CPUs (except APUs) provide 16+4+4 PCIe lanes: Corner with triangle marker (missing pin) is key
| Group | Function | Approx. Count | |-------|----------|----------------| | | CPU core voltage (VCore) | ~200–250 | | VSS | Ground | ~400–500 | | VDD_SOC | SoC / Uncore voltage | ~30–50 | | VDD_MISC | Miscellaneous logic | ~10–15 | | VDDP | DDR PHY voltage | ~10 | | VDD18 | 1.8V standby | ~5 | | DDR4 channels | Memory data/address/control | ~200 | | PCIe lanes | PCIe 3.0/4.0 (depends on CPU) | ~160 | | FCH (chipset) | Promontory chipset link | ~30 | | SATA / USB / GPIO | I/O | ~20 | | Clocks & reset | CLK, PWR_OK, RESET# | ~10 | | SVI2 | Serial Voltage Identification (power management) | 2 | | JTAG / debug | Test/debug | ~10 | 3. Important Pin Signals (Examples) Here are some commonly referenced pins for troubleshooting, modding, or voltage measurement: Row C: C1 (PWR_OK) C2 (VDD) C3 (VDD) C4 (VSS)
