HP dc7900 manual System Power States, State System Condition, Power Transition OS Restart

Power and Signal Distribution

7.3.3 Power Management

These systems include power management functions designed to conserve energy. These functions are provided by a combination of hardware, firmware (BIOS) and software. The system provides the following power management support:

■ACPI v2.0 compliant (ACPI modes C1, S1, and S3-S5)

■APM 1.2 compliant

■U.S. EPA Energy Star 3.0 and 4.0 compliant

Table 7-6 shows the comparison in power states.

Table 7-6.

System Power States

	Power		Power	Transition	OS Restart
	State	System Condition	Consumption	To S0 by [2]	Required
	G0, S0, D0	System fully on. OS and	Maximum	N/A	No
		application is running, all
		components.
G1, S1, C1, D1	System on, CPU is executing and	Low	< 2 sec after	No
		data is held in memory. Some		keyboard or
		peripheral subsystems may be on		pointing device
		low power. Monitor is blanked.		action
G1, S2/3, C2,	System on, CPU not executing,	Low	< 5 sec. after	No
D2 (Standby/or		cache data lost. Memory is		keyboard, pointing
suspend)		holding data, display and I/O		device, or power
		subsystems on low power.		button action
G1, S4, D3	System off. CPU, memory, and	Low	<25 sec. after	Yes
(Hibernation)		most subsystems shut down.		power button
		Memory image saved to disk for		action
		recall on power up.
G2, S5, D3cold	System off. All components either	Minimum	<35 sec. after	Yes
		completely shut down or receiving		power button
		minimum power to perform system		action
		wake-up.
G3	System off (mechanical). No power	None	—	—
		to any internal components except
		RTC circuit. [1]

NOTES:

Gn = Global state.

Sn = Sleep state.

Cn = ACPI state.

Dn = PCI state.

[1]Power cord is disconnected for this condition.

[2]Actual transition time dependent on OS and/or application software.

Technical Reference Guide www.hp.com 7-9