Putting your computer to sleep is easy. If you have a laptop, just close it before you walk way. This automatically activates sleep mode on most laptops. (Closing your laptop has the added benefit of protecting your screen and keyboard from external dangers, such as a curious cat or roaming children.) If you have a desktop computer, you can put it to sleep with a simple command. In Windows, simply select to activate sleep mode. In Mac OS X, you can put your computer to sleep by selecting . The keyboard shortcut Command+Option+Eject also works.
Here are the different modes of "sleep"
Sleep ModeSleep mode is a power-saving state that is similar to pausing a DVD movie. All actions on the computer are stopped and any open documents and applications are put in memory. You can quickly resume normal, full-power operation within a few seconds. Sleep mode is basically the same thing as “Standby” mode.
The Sleep mode is useful if you want to stop working for a short period of time. The computer doesn’t use much power in Sleep mode.
HibernateThe Hibernate mode saves your open documents and running applications to your hard disk and shuts down the computer, which means once your computer is in Hibernate mode, it uses zero power. Once the computer is powered back on, it will resume everything where you left off.
Use this mode if you won’t be using the laptop for an extended period of time, and you don’t want to close your documents.
Hybrid SleepThe Hybrid Sleep mode is a combination of the Sleep and Hibernate modes meant for desktop computers. It puts any open documents and applications both in memory and on your hard disk, and then puts your computer into a low-power state, allowing you to quickly wake the computer and resume your work. The Hybrid Sleep mode is enabled by default in Windows on desktop computers and disabled on laptops. When enabled, it automatically puts your computer into Hybrid Sleep mode when you put it into Sleep mode.
Hybrid Sleep mode is useful for desktop computers in case of a power outage. When power resumes, Windows can restore your work from the hard disk, if the memory is not accessible.