GIGABYTE AMD Socket 939 Processor Motherboard GA-K8N51PVM9-RH - Manual (Page 43)

BIOS Setup - 43 -
English
CPU Smart FAN Control (Note)
Disabled Disable this function. (Default value)
Enabled When this function is enabled, CPU fan will run at different speed depending on
CPU temperature. Users can adjust the fan speed with Easy Tune based on
their requirements.
System Smart FAN Control
Disabled Disable this function. (Default value)
Enabled When this function is enabled, System fan will run at different speed depending
on System temperature.
(Note) Whether the CPU Smart FAN Control function is supported will depend on the CPU you install.
For more detailed information please check at the FAQ section on GIGABYTE's website.