Hibernate is a power-saving state designed primarily for laptops, and might not be available for all PCs (PCs with InstantGo don’t have the hibernate option). While sleep puts your work and settings in memory and draws a small amount of power, hibernation puts your open documents and programs on your hard disk to the hiberfile (C:\hiberfil.sys), and then turns off your computer. Hibernate uses less power than sleep and when you start up the PC again, youâ€™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.
Fast startup (aka: hiberboot, hybrid boot, or hybrid shutdown) is turned on by default in Windows and is a setting that helps your PC start up faster after shutdown. Even faster than hibernate. Windows does this by saving an image of the Windows kernel and loaded drivers to the hiberfile (C:\hiberfil.sys) upon shutdown so when you start your PC again, Windows simply loads the hiberfile (C:\hiberfil.sys) into memory to resume your PC instead of restarting it.
By default, the hiberfile (C:\hiberfil.sys) is 75% of the total amount of RAM installed on your computer.
Fast startup requires that hibernate be enabled. If you only want to use fast startup and don’t plan on using hibernate, then you can specify the hiberfile type as reduced to significantly reduce the size of the hiberfile (C:\hiberfil.sys) to about half of its full size.
This tutorial will show you how to specify the desired hiberfile type to be reduced or full in Windows 10.