What do you mean by crazy? I can hear mine speed up in response to higher CPU loads, it will become audible and go silent again within 30-60 seconds or so, or stay running longer if something intensive is running long term. IE, it responds quickly to changing system load. To me this seems normal.
My laptop fan seems normal on 8.0 and 8.1. It spins up when I first turn the laptop on and then goes quite again. When things get hot it speeds up again.