The BIOS built-in hardware monitoring features are useful for collecting information and monitoring the activity of the hardware connected to the motherboard. The type and number of monitoring features varies by motherboard model. Use the hardware monitoring page to view temperatures, fan speeds, voltages, and other items. This area might also have information about intrusion detection devices.


Motherboards have heat sensors to monitor heat sensitive hardware. A common heat sensor is under the CPU socket. This sensor monitors the temperature of the CPU and might increase the speed of the CPU fan to cool the CPU if it becomes too hot. Some BIOS setups also slow the speed of the CPU to reduce the CPU temperature. In some cases, the BIOS shuts down the computer to prevent damage to the CPU.

Other heat sensors monitor the temperature inside the case or power supply. Additionally, heat sensors monitor the temperatures of the RAM modules, chipsets, and other specialized hardware. The BIOS increases the speed of the fans or shuts down the computer to prevent overheating and damage.

Fan Speeds

Fan speeds are monitored by the BIOS. Some BIOS setups allow you to configure profiles to set the fan speeds to achieve a specific result. These are some common CPU fan speed profiles:


You can monitor the voltage of the CPU or the voltage regulators on the motherboard, as shown in Figure 1. If voltages are too high or too low, computer components can be damaged. If you find that voltages are not at or near the correct amount, make sure that the power supply is operating properly. If the power supply is delivering the correct voltages, the motherboard voltage regulators might be damaged. In this case, the motherboard might need to be repaired or replaced.

Clock and Bus Speeds

In some BIOS setups, you can monitor the speed of the CPU, as shown in Figure 2. Some BIOS setups may also allow you to monitor one or more of the busses. You might need to look at these items to determine if the correct CPU settings have been detected by the BIOS or manually entered by a client or computer builder. Incorrect bus speeds can cause increased heat within the CPU and connected hardware, or cause adapter cards and RAM to malfunction.

Intrusion Detection

Some computer cases have a switch that triggers when a computer case is opened. You can set the BIOS to record when the switch is triggered so that the owner can tell if the case has been tampered with. The switch is connected to the motherboard.

Built-in Diagnostics

If you notice a problem with a device connected to the system or a basic function, such as a fan or temperature and voltage control, you might be able to use built-in system diagnostics to determine where the problem is. Many times, the program provides a description of the problem or an error code for further troubleshooting. These are some common built-in diagnostics:

Many built-in diagnostic programs retain a log that contains a record of the problems encountered. You can use this information to investigate issues and error codes. When a device is under warranty, you can use this information to convey the problem to product support.