Game lags at start of new game, but then improves?

[Grapa]

Whenever I start a new game, it starts off very slow and laggy, but then, after about 30 turns, the game works perfectly and there is no lag whatsoever, even when the entire map is filled. It only happens near the beginning, and then slowly the game speeds up.

I'm playing on max settings. Any reason for this? It's funny, because my processor is crap, although my video card is good...

 

[BrainEater5000]

My game was choppy at the beginnings, but then I turned the cloudy stuff to minimal. It made the game a heck of a lot smoother for me.