When I play, it not only crashes from time to time.. In the midst of battle it slows down so a second on the battle field is about 13 i realtime.. so it is actually not playable in battles as this happens about half of the battles, it just kills the fun out of it.. though I have used the patches that comes automatically with steam (yes I bought the game)... It feels terrible spending almost 100 dollars on it (Norwegian price) I just want to return the game now..
Slowdown isn't the same as a crash.
Total War has hundreds of units on the screen at once, you need a powerful machine to handle this.
You could probably improve your experience by turning down the resolution and detail for the battle.