Originally filed in September 2008, Intel’s has been granted the patent by the USPTO on March 27, 2012. The patent describes a process to calculate the fan speed that will decrease platform power the most.
More specifically, the patent refers to CPUs that operate in a low temperature state with a fan running at low speed. Intel says that the power saved from the processor can be used to power the fan itself. The process to determine the perfect fan speed would include:
- measuring the processor power and the fan power when it is initially determined that the processor is operating in a low temperature state prior to any fan speed adjustments
- calculating the system power prior to any fan speed adjustments
- increasing the fan speed
- measuring the processor power and the fan power for the increased fan speed
- calculating the system power for the increased fan speed
- dynamically adjusting the fan speed based on changes to the system power
- measuring the processor power and the fan power for the dynamically adjusted fan speed
- calculating the system power for the dynamically adjusted fan speed
- selecting the preferred speed when the system power is determined to be substantially at lowest value
Interestingly, the patent itself doesn’t describe a way to keep the CPU from going over a certain temperature limit, but more of a constantly running fan to reduce the power consumption of the CPU, also referring to the power leakage problem caused by the high CPU temperatures.
Source: Tom’s Hardware UK