HDG Explains - Swapfile.sys, Hiberfil.sys and Pagefile.sys in Windows 8
In previous versions of Windows, you probably remember the good ol paging file. It’s used to when physical memory becomes overcommitted and it hold objects that usually have not been accessed in a long time. That is pagefile.sys. Next, we had the hibernate option in Windows that let you save the kernel and all applications to your hard drive so that you could start your computer back up faster than doing a full reboot. That is hiberfile.sys.
In Windows 8, things get more complicated. The pagefile.sys is there all the time, but the hiberfil.sys is only there if you have fast startup enabled in Windows 8. What is fast startup? It basically allows Windows 8 to perform a hybrid shutdown. This is why Windows 8 boots up so much faster than previous versions of Windows. Check out my previous post that explains what a hybrid shutdown is in Windows 8.
In order to use the new hybrid shutdown feature, which is turned on by default, hibernation has to be enabled in Windows 8. If hibernation is disabled, you won’t have a hiberfil.sys file and you won’t be able to use the fast startup option either. You can read my post here about enabling hibernation in Windows 8.