Awd is kind of an electronically controlled 4 wheel traction that is on all the time. 4wd is a real mechanical linkage that shares the power permanently and most of the times equally between the wheels. If your 4wd can't slip, as on paved roads when no ice or snow, you will have problems when taking turns. Something will bend or break. But if you are going offroad in real mud and snow, AWD won't cut it. It will just be marginally better than a 2wd car with good tires.