Opening up the unit reveals a couple decent sized capacitors but relatively puny heatsinks. Their size (as well as that of every other component) is no doubt limited by the thickness of the fan which spans most of the top. Speaking of which, it's a 120x25mm blower (model name D12SM-12) made by Yate Loon Electronics and rated at 12V, 0.3A, and 1650RPM providing 56CFM at 39dBA. By default the fan runs at a fraction of its voltage, referred to by Nexus as its "idle mode". At this level it's rated at 16.2dBA which is inaudible beyond a couple inches. It speeds up in a linear fashion as the temperature rises (and increases in noise as well as airflow), though having used it for almost a week now I haven't witnessed any apparent changes in airflow.