I think I know what Karpov is talking about. I have manual hubs. If I engage 4x4 High + lock the hubs, the handling does stiffen up quite a bit at higher speed (above 40 km/h).
SO... if the road condition is not too bad, I just to engage 4x4 high using the button but do NOT lock the hubs. That seems to give me a "good enough" approximation of "all wheel drive". I.e. I can launch from mud and snow, and have passable handling on the slippery pavement.