With Truffle E/EC/EF/EX here is the BIOS settings for fan control:
You may connect a USB keyboard and a monitor and press <DEL> to come to the BIOS prompt. Under Advanced you can select the following option:
HW Monitor->Smart Fan Mode Configuration -> SYS Smart Fan Mode -> Thermal Cruise Mode
HW Monitor->Smart Fan Mode Configuration -> CPU Smart Fan 0 Mode -> Thermal Cruise Mode
HW Monitor->Smart Fan Mode Configuration -> CPU Smart Fan 1 Mode -> Thermal Cruise Mode