In response to customer feedback regarding reducing the noise of our rack computers, G2 Digital’s engineers have been designing an independent PCB to control the system fans’ speeds based on CPU temperature.
Conventional PWM cooling fans (4-pin), which can control the speed of the CPU fan, have existed for some time. However System (or case cooling) fans have not been able to utilize this feature as the motherboard often only has a 3-pin header which is missing the speed control pin. This results in the majority case of cooling fans running at full speed creating unnecessary noise, using excessive power and reducing life expectancy.
The controller board we have developed has a 4-pin Molex power input and 3-pin fan headers to drive up to three fans. A thermistor located on the CPU cooler feeds back the internal ambient temperature to the PCB which then adjusts the output voltage to the fans which can run between 50-100% load.
Often PWM is used to modulate the output signal to the cooling fans but for some types of fan this isn’t suitable due to the sensitive circuitry inside. Our controller instead modifies the output voltage between 6-12V making it suitable for all types of fans.
The primary benefit of this controller is to enable our systems to run quieter and increase the life of the fans. Shortly we will be performing some noise measurements tests on our 1U rack mounted computers so the data should be available here shortly. However, based on some initial work we now believe we make some of quietest actively cooled rack computers on the market.