Sleep: Press the Sleep key on the keyboard, or click Sleep from the Power menu (Windows 10), or under the Shut down menu in (Windows 8) to put the computer in sleep mode. Closing the display panel on a notebook can also put the notebook in sleep mode. Sleep mode saves the state of all open applications to memory, then powers down both the display panel and hard disk drive. Only enough power is used to maintain the data in the memory. Restoring from sleep mode happens quickly, in most cases in a matter of seconds. Sleep mode is useful when you need to pause the computer for a short time. However, in a notebook, maintaining the power to the memory modules can drain a battery if the notebook is not plugged in.
Hibernate: Click Hibernate (if available) from the Power menu (Windows 10), or under the Shut down menu (Windows 8) to put the computer in hibernate mode. Hibernate saves the state of all open applications to the hard disk, then completely powers off the computer. The computer consumes no power while in hibernate mode. When you restart the computer, the previous state of all open applications is restored. Restarting from hibernate mode might take longer than restarting from sleep mode. Use hibernate when you do not need your computer for an extended period of time.