Sleep vs. Hibernate
What does Sleep mean?
Sleep/sleep mode/ standby is simply a power saving state which stops all the actions on the computer. All the open documents and running applications are put in memory. With sleep mode, you can quickly resume normal full-power operation within a few seconds. The computer stops what it is doing immediately and is ready to start when you want it to resume working. The computer does not use much power in sleep mode. Sleep mode is important when you want to stop working only for a short period of time.
What does Hibernate mean?
Hibernate/shut down is a power saving state that is designed basically for laptops. Hibernation puts your open documents and programs on the hard disk and then shuts down the computer. Once the computer is in hibernation mode, it uses virtually zero power. Once the computer is powered back on, it resumes everything from where you left it off. Hibernation uses the least amount of power.