With brand new techniques in place it takes 8 seconds to do a cold-boot on windows 8.
You must have heard that Windows 8 has built new boot algorithms to make booting very fast. In this video one of the developers show how long you actually have to wait on a laptop for it to boot. (Hint: 8 seconds, yup that fast)
In order to achieve “fast start-up” mode, Microsoft basically sets the computer’s kernel to hibernate, which is typical during shutdown. A cold power-off and restart would probably take a little longer—about eight seconds, the company surmises. The faster boot time is supposed to benefit all PCs, whether you’re running an old school hard drive or a snappy SSD in your computing rig.