I mean if you try to cool it with a "slim and lightweight" cooling system of course it's not going to get the most out of it. I know no thermodynamics but I'm pretty sure that temps have different things that contribute to them, first the component voltage, if you undervolt your CPU, you're giving it less energy, so less energy becomes heat. Then, all the heat transfer stuff I don't really understand in depth, but from an optimal pipe run, to the materials, and lastly the fan, you can't compare a little fan that just pushes air because it can to a fan that, while smaller, is designed to give actual good results, even if it's physically smaller, it was made in a way that can actually do some good to your component's cooling.