Increase fan speed in BIOS/UEFI
Set the fan control mode to PWM or DC correctly
Change the fan curve to run faster at lower temperatures
Disable silent or quiet fan profiles
Use motherboard fan control software
Set the system to performance mode in the operating system
Clean dust from fans, heatsinks, and vents
Improve case airflow
Reseat the CPU cooler
Replace old thermal paste
Check that the CPU fan is connected to the correct header
Update BIOS/UEFI firmware
Update motherboard fan control software
Replace weak or failing fans
Use higher-RPM fans
Reduce cable obstruction near airflow paths