Sleep Mode
Sleep 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.
Hibernate
The 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.
Source : Howtogeek
