I recently installed an ASRock H81 board in a new build (DESK2 in sig below...) and have a Fractal 3-pin fan hooked up to the 4-pin case fan header, but it's running at a default 1200+/- RPM and is kind of noisy.
Does the ASRock board have a way to undervolt that case fan header? There is case fan control in the BIOS, but I'm guessing that's for a 4-pin PWM. I'm not that familiar with the ASRock BIOS...
Hardware Health Event Monitoring Screen in UEFI
CPU Fan 1 & 2 Setting
Select a fan mode for CPU Fans 1&2, or choose Customize to set 5 CPU
temperatures and assign a respective fan speed for each temperature.
Chassis Fan 1 Setting
Select a fan mode for Chassis Fan 1, or choose Customize to set 5 CPU temperatures
and assign a respective fan speed for each temperature.
Chassis Fan 2 Setting
Select a fan mode for Chassis Fan 2, or choose Customize to set 5 CPU temperatures
and assign a respective fan speed for each temperature.
Set the target temperature between 45 and 55 (when this value is exceeded, the fans will speed up to maintain that temp)
Set target fan speed to the lowest value your fan will except. Some fans will not start if this value is to low (this is the default speed of your fans when the temperature of the CPU is below the target temperature).
After you make the change, save and exit. The change should reflect on boot. Keep doing it until its as quiet as you want AND the CPU is able to remain cool..
If you want to fine tune it more, Asrock has the A-Tuning utility that comes with the board. Use the FAN-Tastic Tuning utility by setting up the graph.
Make sure you verify the fan speed changes (either in bios or using windows utility).