Lenovo 20AA000955, Hardware Maintenance Manual, Page: 41 / 118

Power management
To reduce power consumption, the computer has two power management modes: sleep and hibernation.
Sleep mode
When the computer enters sleep mode, the following events occur:
• The LCD is powered off.
• The solid-state drive is powered off.
• The microprocessor stops.
To put your computer into sleep mode, open the Start menu, click Power , and then click Sleep .
In certain circumstances, the computer goes into sleep mode automatically:
• After a period of inactivity specified in power plan settings
• When the battery power is low
To cause the computer to return from sleep mode and resume operation, do one of the following:
• Press any key.
• Open the LCD cover.
• Turn on the power button.
Also, in either of the following events, the computer automatically returns from sleep mode and resumes
operation:
• The ring indicator (RI) is signaled by a serial device or a PC Card device.
• The time set on the resume timer elapses.
Note: The computer does not accept any input immediately after it enters sleep mode. Wait a few
seconds before taking any action to reenter operation mode.
Hibernation mode
In hibernation mode, the following occurs:
• The system status, RAM, VRAM, and setup data are stored on the solid-state drive.
• The system is powered off.
Note: If the computer enters the hibernation mode while it is connected to the dock, do not disconnect it
before resuming normal operation. If you do disconnect it and then try to resume normal operation, you will
get an error message, and you will have to restart the system.
If you have defined one of the following actions as the event that causes the system to go into hibernation
mode, perform that action.
• Closing the lid.
• Pressing the power button.
Also, the computer goes into hibernation mode automatically after a period of inactivity specified in power
plan settings.
When the power is turned on, the computer returns from hibernation mode and resumes operation. The
hibernation file in the boot record on the solid-state drive is read, and system status is restored from the
solid-state drive.
Chapter 4
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Related service information
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