My PC's fans running crazy on start game

everytime I start game, on logging screen or before it(a dark bloody mist with fire particle), my PC's fans would suddenly went crazy like to exploding.

then, it cool down a little.

not strange when in maps with lots effects, but why on start? there is no comlex or mass effects.

Most likely shader compilation, even if the game has already done it, there will always be a small shader comp when firing up the game, which primarily uses your CPU to do, so temps would spike.

I'm only deducing from the small info you gave, so i could very well be wrong.