SpeedFan monitor temperatures from several sources. By properly configuring SpeedFan, you can let it change fan speeds based on system temperatures. When choosing parameters for the minimum and maximum fan speed, try to set them by hand (disable all the VARIATE FANs checkboxes) and listen to the noise. When you hear no noise from the fan then you can set that value as the minimum fan speed for that fan. I suggest to use 100 as the maximum value, unless you hear a lot of noise from it, in which case you might reduce the maximum speed to 95 or 90. You can set, say, 60 as the maximum value and, sometimes, I myself set it that way. Consider that when the WARNING temperature is reached, the program sets the fan speed to 100, whatever maximum speed you selected. One last word should be said regarding the USE FAN x listbox. In my pc, more than one temperature changes when a fan runs faster. You can configure on which fan every temperature should rely. On my system, TEMP1 and TEMP3 are both influenced by FAN1.