After rebooting my Windows 8 laptop, I can instantly login with my password, as I would expect.
However, if I use my PIN instead, the system mostly freezes for about one minute: The input box disappears, the "back"-Button becomes unresponsive. After one minute, the login is executed as expected.
Some things still work in this "freeze": I can switch the keyboard layout, and this "slide-up-to-unlock"-lockscreen engages after a few seconds of inactivity.
This problem only occurs directly after a reboot. After hibernation or logging off, there is no delay, and if I reboot and wait a few minutes before logging on, there is no delay, too.
The picture password login has the same problem, while using the password works fine.
What is happening here?