To turn Fast Start off, do the following:
- Open Control Panel then select Power Options.
- Activate the Choose what the power button does link on the left side of the dialog.
- In the dialog just opened, activate Change settings that are currently unavailable link.
- Scroll down to the Shutdown settings section.
- Remove the check mark from the Turn on Fast Startup (Recommended) checkbox.
- Select the Save Changes Button.
Another name for the Fast Startup is Hybrid Boot.
With a full shutdown everything is closed and nothing is saved.
When the Fast Startup is enabled and the computer is shut down, the User Session is closed, but the Kernel Session is Hibernated. You are not doing a full shutdown, but a partial shutdown and partial hibernation.
From a Microsoft Forum discussion regarding Fast Startup:
“Now here’s the key difference for Windows 8: as in Windows 7, we close the user sessions, but instead of closing the kernel session, we hibernate it. Compared to a full hibernate, which includes a lot of memory pages in use by apps, session 0 hibernation data is much smaller, which takes substantially less time to write to disk.
If you’re not familiar with hibernation, we’re effectively saving the system state and memory contents to a file on disk (hiberfil.sys) and then reading that back in on resume and restoring contents back to memory. Using this technique with boot gives us a significant advantage for boot times, since reading the hiberfile in and reinitializing drivers is much faster on most systems (30-70% faster on most systems we’ve tested).”
I don't care how much faster it's claimed it can make startup compared to a "from scratch" startup. When I power down my computer I expect that upon firing it up again the OS will be reloaded from scratch. I've also seen some "interesting" things happen when the partial hibernation file becomes corrupted.