Sleep State Types

Power management is an integral feature of most new computers. With laptops and wireless computing on the rise it is especially important to have strict control and reliability when it comes to your systems power states.

Power State	Description
Working	The system is fully on. Some devices may independently conserve power if there usage falls below a certain threshold.
Sleeping	The system seems as though it’s shut down. Power consumption is reduced to one of the three sleep levels (see below). The lower the level, the more power that is conserved, but the longer it takes for the system to wake. Mouse movement or key presses will usually wake the system.
Soft Off or Hibernate	The system appears to be off. Power consumption is very low. The operating system context is saved out to disk and no longer exists in RAM. Wake up usually results in hardware boot, but not software boot.
Mechanical Off	No power consumption. A full reboot will be required to start up the system.

Hybrid sleep is where the hibernation file is used in conjunction with sleep states S1-S3 so the system state can be restored if power is lost while sleeping.

ACPI (Advanced Configuration and Power Interface) is an industry wide standard that defines a power management and configuration mechanism for hardware and operating systems. ACPI defines six discrete power states. Lower states consume more power, but have a smaller latency on wake up.

S0 – Working
S1 – Sleeping
S2 – Sleeping
S3 – Sleeping
S4 – Hibernate
S5 – Off

Sleeper allows the user to put the system into sleep state S1, S2, S3 or S4. To turn off or reboot the computer, see the Rebooter application also available from PassMark.
Note that not all computer systems will support all power states. It is not unusual for just S1 and S4 to be supported or S1, S3 and S4. Attempting to put a system into an unsupported state results in the next lowest supported state being chosen.