Apple Power Mac G5 - Manual (Page 19)

Innovative Enclosure
Design for Quiet Operation
An industry-leading system demands an exceptional enclosure design. The Power Mac
G5 features a modern chassis constructed of anodized aluminum. Inside, an efficient
cooling system uses low-speed fans for superquiet operation—twice as quiet as a
Power Mac G4.
Intelligent Cooling System Using Low-Speed Fans
The new Power Mac enclosure is divided into four discrete thermal zones, compart-
mentalizing the primary heat-producing components: processor, PCI, storage, and
power supply. This allows the system to increase or decrease the temperature of a
single zone without affecting the others—and without unnecessary cooling. The
front panel is 35 percent perforated, so cooler outside air can enter, flow over the
heat-producing components, and exhaust out the perforations in the rear panel. For
added cooling efficiency, an internal air deflector channels airflow over the processor
heat sinks and the PCI slots.
Each thermal zone is equipped with its own fans. Apple has engineered seven of the
nine fans to spin at very low speeds for minimum acoustic output. Using 21 different
sensors, Mac OS X constantly monitors component temperatures in each zone and
dynamically adjusts individual fan speeds to the appropriate levels, achieving the
quietest possible operation.
19 Technology and
Performance Overview
Power Mac G5