Cold boot, or hybrid hibernation?
Truth about the fast boot in 8 being a hybrid hibernate and not a full shutdown.
When running a windows gadget that shows uptime on it, I shutdown. Then start back up, and the uptime meter never stopped running. Even after being "shutdown" for 8 hours.
A restart, however, resets the uptime meter to zero.
All the online info about fast boot says that a restart isn't affected.
This shows that Windows 8, with fast boot enabled, doesn't actually shut down, it goes into hybrid hibernation mode, hence the ability to seemingly boot up in 10 seconds or so, with a UEFI BIOS and UEFI OS.
How Windows 8 Hybrid Shutdown / Fast Boot feature works