Description: What is the Fast Boot feature on Windows 8?

In older versions of Windows the system would send messages to running applications and devices to close completely down whenever a user would use the Shut Down option. With Windows 8, the system instead puts Windows in hibernate mode when the User shuts the computer down. By doing this it results in a faster startup performance, also known as Fast Boot. The startup is faster since Windows is in a hibernate state and on startup it will resume Windows. The Fast Boot also takes advantage of multiple CPU cores that allow the system to process at a faster rate.

For more information on Fast Boot, please check out Microsoft's blog below.
https://blogs.msdn.microsoft.com/olivnie/2012/12/14/windows-8-fast-boot/