Desktop Motherboard Power Sequence Pdf Jun 2026

The CPU begins executing code from the BIOS chip (SPI Flash).

When you press the power button on your desktop, a highly choreographed, instantaneous dance of electricity occurs before you see a single image on your screen. This intricate process is known as the .

The PSU provides a small amount of electricity, specifically +5VSB (Standby Voltage) , to the motherboard.

For locating specific pins and rails. 4. Download: Desktop Motherboard Power Sequence PDF

Even when the PC is off, a small amount of power is present as long as the PSU is plugged in and switched on. desktop motherboard power sequence pdf

If you are compiling this data into a troubleshooting manual, you can save this layout directly into a printable for quick bench reference.

Finally, the Northbridge/PCH sends a Reset signal to the CPU itself, telling it to start executing the first line of code from the BIOS/UEFI chip.

The memory (RAM) is powered on, and the power management circuitry ensures that the memory voltage and timing are adjusted according to the system's requirements.

Shortly after, the PCH or specialized voltage translation logic asserts (CPU Reset) high. The CPU begins executing code from the BIOS chip (SPI Flash)

Both Intel and AMD provide extensive documentation and for motherboard manufacturers, which include the authoritative power sequence requirements for their specific chipsets and CPUs. These guides can be found on each company's official developer website.

These raw voltages are converted by local regulators into specialized power for components like RAM (1.2V–1.5V) and the Chipset (1.05V). 4. The CPU and VRM Handshake

System state is saved to the hard drive. Hardware state is identical to S5.

Pressing the physical button pulls a dedicated active-low pin on the motherboard down to 0V (Ground). The PSU provides a small amount of electricity,

The system is fully operational. All power rails are active. 2. Phase 1: Standby Power and RTC Circuit (G3 to S5)

If the PCH determines that all standby parameters are valid, it begins exiting its sleep states.

The SIO chip receives the high SLP_S3# signal from the PCH. Recognizing that the system is cleared to turn on, the SIO pulls Pin 16 of the 24-pin ATX cable () down to 0V (Ground).