While computer components (e.g., CPUs, chipsets, graphics cards, hard disk drives, etc.) are designed to generate as little heat as possible, these components nonetheless produce heat during operation and thus require a cooling system to dissipate the heat produced. Heat mitigation measures are taken to prevent overheating of components, which may lead to temporary or permanent damage to the components. Computer cooling is required to remove the waste heat produced by the components so that temperatures may be maintained within certain operating limits so as to avoid such damage.
Computers are often equipped with active cooling systems that require energy to cool critical components. These cooling systems can include forced-air devices driven by fans or liquid cooling mechanisms driven by pumps. For example, heatsinks attached to the components may be actively cooled by airflow induced by computer fans to reduce a rise in temperature. Furthermore, attention to patterns of airflow can also help prevent the development of hotspots. Conventional cooling systems operate in similar fashion to that of a thermostat, where cooling is activated when temperatures are sensed to be rising beyond a certain threshold level. These cooling systems, however, provide an optimization problem for designers striving to minimize the energy required to cool system components.
In optimizing cooling systems, two common goals are in tension. A first goal is to minimize thermal margins, that is, minimize how far the current operating temperature is below the maximum operating temperature of the processor so that minimal energy is consumed to maintain an allowable temperature. And a second goal is to avoid temperature excursions in excess of thermal specification temperatures when the system is subjected to dynamic power loadings. The first goal generally calls for reducing energy used by the cooling system and the second goal generally calls for increasing energy used by the cooling system.
In practice, fans do not always run at constant speed. In fact, most computers have dynamic fan speed control (FSC) algorithms that react to on-board temperature sensors. FSC algorithms can be subject to frequent changes in component power that result in frequent changes in temperature climates, thus exacerbating issues related to cooling of the components. For example, overcooling may occur when fan speeds are too high. While this situation doesn't threaten the performance of the components, overcooling results in wasted power. Overcooling may also produce excessive sound levels from the running fans. In some instances, the vibration from higher fan speeds has the potential to cause performance degradation in storage devices. Undercooling may also occur when fan speeds are too low, resulting in critical components exceeding maximum operating temperature limits. Additionally, time delays may result from current dynamic fan speed control algorithms, since changes in fan speed may be too slow to cool a system subjected to rapid changes in power consumption or ambient temperature. Optimization is further complicated by the fact that component temperatures may increase or decrease more rapidly as thermal design power (TDP) increases. This makes optimization more difficult as designers strive to maintain small thermal margins in order to minimize power consumption and airflow.
With the continual increase in computing power from more advanced processors and associated components come the challenges of effectively managing temperature of computer components. Thus, there exists a need for a control system that can more efficiently and more intelligently handle computer cooling.