Sleep
This uses very little power, your PC starts up faster, and you’re instantly back to where you left off. You don’t have to worry that you'll lose your work because of your battery draining, because Windows automatically saves all your work and turns off the PC if the battery is too low. Use sleep when you’re going to be away from your PC for just a little while—like when you’re taking a coffee break.
Hibernate
This option was designed for laptops and might not be available for all PCs. (For example, PCs with InstantGo don't have the hibernate option.) Hibernate uses less power than sleep and when you start up the PC again, you’re back to where you left off (though not as fast as sleep).
Use hibernation when you know that you won't use your laptop or tablet for an extended period and won't have an opportunity to charge the battery during that time.