Shut down
This is the power-off state most of us are familiar with. When you shut down your computer, all your open programs close and the computer shuts down your operating system. A computer that’s shut down uses almost no power. However, when you want to use your computer again, you’ll have to turn it on and go through the typical boot-up process, waiting for your hardware to initialize and startup programs to load.
Sleep
Also known as standby. In sleep mode, the computer enters a low-power state. Power is used to keep the computer’s state in memory, but other parts of the computer are shut down and won’t use any power. When you turn on the computer, it snaps back to life within just a few seconds. You won’t have to wait for it to boot up: everything will be right where you left off. However, this uses more power than shutting down or hibernating your computer.
Hibernate
Your computer saves its current state to your hard drive, essentially dumping the contents of its RAM into a file on its hard drive. When you boot up the computer, it loads the previous state from your hard drive into its RAM. This saves your computer’s state, including all your open programs and data, so you can come back to it later. It takes longer to resume from hibernate than sleep, but hibernate uses much less power than sleep. A computer that’s hibernating uses about the same amount of power as one that’s shut down.
