I bought a new Lenovo Z50 laptop, i7 with 8gig ram. I have bad luck with laptops crapping out on me after 2 years due to over-heating. This time I want to try a laptop cooler, but how good are they at doing what they promise to do? Many laptops these days don't have vents on the bottom. So how does a cooling pad keep the system cool if it can't push cool air into vents below? I'm looking at Coolmaster series but should I go with the one with one massive fan or the ones with smaller 3 movable fans work better at keeping things cool?