the map size shouldn't matter. How many submarines are you talking? I'm not sure if they're as resource hungry as airplanes or not, but I've had swarms of planes overhead (probably on the order of 2 dozen...
) in some battle scenes, and do notice a slowdown, but no CTD. You choose the mission from the menu, and does it get to the background saying (which I can't remember the stock one), or do you just go to black, and it never comes back, but just crashes, and you get the "Silent Hunter has stopped..." kind of error message?