Processors produce varying levels of heat depending on system load, thus it makes sense to reduce the speed of the fans during idle to decrease the noise produced by fans running full speed, until the load does goes up, at which point fan speed must be adjusted promptly to avoid overheating. Modern hardware monitor chips, once configured, are capable of independently running this monitoring loop without any need for a functioning BIOS or an operating system. This automatic control offered by some chips may be called Thermal Cruise mode for maintaining a thermal envelope, as well as Fan Speed Cruise mode for maintaining a specific fan speed automatically.