Working Principles of Software Coolers

Working Principles of Software Coolers

Most software coolers issue special halt commands when the CPU is idle. An idle processor consumes less power, and thus, generates less heat. Similar functions are included in newer operating systems, such as Windows NT/2000/XP/Server 2003 and Linux. These operating systems perform the so-called halt cycle in low-priority tasks. During this cycle, the processor core temporarily stops; other subsystems continue to operate.

When the CPU is cooled by the traditional heatsink and fan, the temperature of its case drops. Because of this, software tools supporting these functions became known as software coolers.

As a rule, software coolers are most efficient under nonuniform processor workloads. Such a situation is created when the CPU executes tasks that require relatively long cycles of data transfer, which do not require the processor's participation. When the processor is loaded to the limit of its capabilities, software cooling based on the previously described principles becomes less efficient. In this case, traditional hardware solutions play the key role.

Still, some software coolers can dynamically increase their priority depending on the CPU temperature, improving their efficiency in Windows NT/2000/XP/Server 2003. In this case, idle clock cycles will increase, the temperature will decrease, and all other programs will slow.

Many tools that ensure the software cooling of processors were created for Windows 9x. This family of operating systems still retains its leading position in some areas. Table 9.1 gives data on the prevalent operating systems used by visitors to our Web site, accumulated during a fixed period.

Table 9.1: Evaluation of Prevalence among Windows Operating Systems

Operating system

Percentage of users (%)

Windows 98


Windows XP


Windows 2000


Windows NT


Windows 95


Windows ME