"This project was originally started as a quest for a
small and silent HTPC (Home Theater Personal Computer). We have
constructed and built several of these boxes. The latest and best
design can be seen further down the page in Figure One.
"These HTPC systems are cooled passively in the sense that no
fans are involved in the cooling of the CPU. The technique used for
the cooling turned out to be rather efficient, that is, adequate
cooling can be achieved without making the system significantly
larger. For instance, the HTPC shown in Figure One (below) has the
dimensions 29 x 27 x 10 cm (11.4 x 10.6 x 4 inches), and even if a
fan were to be used it would not be trivial to build a smaller
system with the chosen components. We will say more about the
design principles as they apply to personal clusters later in the
article."