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ACPI State Explanation

ACPI State Explanation
Photo by Thomas Kelley / Unsplash

TL;DR:

  1. S0: Also known as the working state, the computer is fully operational with the CPU executing instructions, devices powered on, and the display active.
  2. S1: Also known as the sleep state, the CPU stops executing instructions, but the memory and system state are still powered on to allow for quick wake-up times.
  3. S2: Similar to S1, the CPU enters a lower power state to provide additional power savings.
  4. S3: Also known as the suspend to RAM state, the system state is saved to RAM, and the computer is placed into a low-power state.
  5. S4: Also known as the hibernate state, the system state is saved to disk, and the computer is fully powered off.
  6. S5: Also known as the soft-off state, the computer is powered off, but some devices (such as the network card) may still be powered on to allow for remote wake-up.
  7. S6: Also known as the power-off state, the computer is powered off, and all power to the system is removed.
  8. S7: Also known as the unknown state, this state is reserved for future use.
  9. S8: Also known as the system off (soft), the computer is powered off, but some components (such as the power supply) may still be operational to allow for remote wake-up.
  10. S9: Also known as the extended system off state, the system is completely powered off, and all power to the system is removed.
  11. S11: Also known as the non-volatile sleep state, the system memory is saved to a non-volatile storage device before the system is powered off, providing faster wake-up times and better power savings compared to the S3 state.

S0

The S0 ACPI state, also known as the "working state" or "fully-on state", is the normal operating state of a computer where the system is fully powered on and all components are active. In this state, the CPU is running, the RAM is active, and all devices and peripherals are ready to use.

S1

The S1 ACPI state, also known as "standby" or "sleep", is a low-power state that is more power-efficient than the S0 state, but less efficient than the S3 state. In the S1 state, the CPU is stopped, but the RAM remains active, and other devices such as the hard drive and fans may be turned off or slowed down.
S2

S2

The S2 ACPI state, also known as "standby with CPU off" or "sleep with CPU stopped", is a deeper low-power state than the S1 state. In the S2 state, the CPU is stopped and the RAM remains active, but more components are turned off or slowed down than in the S1 state.

S3

The S3 ACPI state, also known as the "suspend to RAM" state, is a power-saving mode that allows a computer to quickly resume from a low-power state. When a computer enters the S3 state, it saves the current state of the system in RAM and then shuts down most of its components, including the CPU and hard disk. However, the RAM remains active, keeping the system's state intact.

S4

The S4 ACPI state, also known as "hibernation" or "suspend to disk", is a low-power state that saves the current system state to the hard disk and then powers off the computer completely. In the S4 state, the RAM is no longer active, and the system consumes no power.

S5

The S5 ACPI state, also known as the "soft-off" state or "mechanical off", is the lowest power state of a computer. In the S5 state, the computer is completely powered off, and there is no power consumption or generation of heat.


S6 - S11: Additional reveal by ChatGPT (not implemented yet)

S6

The S6 ACPI state, also known as the "standby power mode" or "soft off with power supply on", is a lower power state than the S5 state. In the S6 state, the system's power supply remains on, providing power to certain components, while the rest of the system is powered off.

S7

The S7 ACPI state, also known as the "platform power management state" or "reserved", is a hypothetical power state that was proposed in the ACPI specification but has not been implemented in any commercial computer systems.

S8

The S8 ACPI state, also known as the "system off" or "mechanical off with AC power applied" state, is a hypothetical power state that was proposed in the ACPI specification but has not been implemented in any commercial computer systems.

S9

The S9 ACPI state, also known as the "extended system off" or "mechanical off with AC power removed" state, is a hypothetical power state that was proposed in the ACPI specification but has not been implemented in any commercial computer systems.

S10

The S10 ACPI state, also known as the "off" state, is a hypothetical power state that was proposed in the ACPI specification but has not been implemented in any commercial computer systems.

S11

The S11 ACPI state, also known as the "non-volatile sleep" state, is a power state that was added to the ACPI 6.0 specification. It is a new low-power state designed to provide an intermediate level of power savings between the S3 (sleep) state and the S4 (hibernation) state.