I bought several inexpensive case fans a few months ago. They move plenty of air, but they are much louder than I expected. They're currently powered through Molex connectors, and each fan also has a 3-pin connector. My motherboard only has one available 4-pin system-fan header in addition to the CPU-fan header, so I'm considering using a fan hub. Can 3-pin fans still be controlled through the BIOS, and would I need to adjust their voltage manually? I believe 4-pin fans use PWM control, while 3-pin fans require DC voltage control. My motherboard is likely a Gigabyte B450M DS3H.
2 Answers
Check the motherboard’s hardware-monitoring or fan-control settings. Most boards, including many Gigabyte B450 models, support both PWM control for four-pin fans and DC control for three-pin fans. Make sure the hub is designed to pass the control signal and is powered safely; some hubs only distribute power and do not provide individual speed control.
In the BIOS, set the system-fan control mode to DC or voltage control instead of PWM. Three-pin fans can be speed-controlled by lowering their supplied voltage, as long as the motherboard header or hub supports that feature. Since the fans are currently connected directly to Molex, the motherboard cannot regulate their speed through those connections.
Thanks, I’ll look for a guide showing where that setting is in the BIOS.