Small and pocketable fanless PCs are often underpowered Atom-based systems. But serious passive cooling often means larger coolers / enclosures. The palm-sized Intel NUC requires 2kg+ aluminum cases to handle heavy loads, while the enormous Nofan CR-95C or the upcoming Noctua fanless CPU cooler fit in tower PC cases only. Very small or totally silent, the choice is up to you.
