this is for notebook yes? i am not too familiar with this one, but for OC, it is usually the unlocked (k) version that can be OC'd, save for a few model.
so i am not sure. but, being a notebook, i think that you will probably encounter temperature issues, it is cramped and hot enough as it is. so overclocking it will add more heat.
also, isn't "u" suppose to be low power type?