If the fan is running at very high speed, there is a known issue related to this. I don't have the CR number available right now, but it should be fixed in the latest patch of EXOS 15.5.3.4, which is the recommended version for the X430.
Hi Arman,
The fan speed on newer products is tied to environmental temperature and in some models, tied to processor temperature. Older products have a "binary" fan.
Which model(s) are you curious about and we can at least give you some insight as to whether or not the fan speed is relative to temperature.