I've set the unit size to small. I don't know too much about drivers, so how do i figure out if my video drivers are what the game needs?

Even though it has been frustrating with the game crashing every 10 or 15 minutes its been really good. Have only had a chance to play as the hapsburg's so far, knocking over a few rebels and stuff, not looking forward to trying it on with the Ottoman's. It'd be really great if i could get the game to run properly!