Why Is My Laptop Making a Buzzing Noise and How to Reduce or Fix it.

In certain situations, an intermittent, high-frequency buzzing noise may be heard from your system. It appears to change with processor activity and can increase in frequency if USB devices are attached. This buzzing noise is noticeable on all laptops but seems abnormal because it differs from the usual computer sounds.

The noise has been isolated to the processor’s power circuit and is only audible when the processor is in C3 (clock-stopped) power state. In this state, the computer is in a low-power mode designed to reduce chassis heat and extend the battery life. The changes to the components in the processor's power circuit are caused by a phenomenon referred to as the Piezoelectric Effect . When a specific voltage is applied to these components, they begin to resonate producing sounds that fall within the range of human hearing (15 - 20 KHz).

The noise is normal and within the acoustic specifications of the computer.

Enable Bus Mastering Devices to Prevent the Processor From Entering C3 Power State

Enable bus mastering devices, such as the onboard Bluetooth radio, to prevent the processor from entering the C3 power state. This prevents the intermittent, high-frequency buzzing noise from occurring. However, when the system is running on battery only, the battery's operational time is reduced.

To enable the Bluetooth radio:

1. Right-click the Bluetooth icon in the system tray.
2. When the Bluetooth Settings menu appears, left-click Power On if it is displayed in the menu. If Power Off is displayed, the Bluetooth radio is already enabled.

There are other reasons computers make noises such as a loud CPU fan, slight buzzing, or a humming noise. See the following Dell Knowledge Base articles for help with determining and reducing or with eliminating the sound.

• Troubleshoot Noise Coming from the AC Adapter
• Audio Distortion or Speaker Static Noise on Select Dell Latitude, XPS, Inspiron, Precision, and Vostro Laptops
• A Guide to Identifying the Source of an Abnormal Noise on a Dell Computer
• How to Identify and Resolve Noise Issue on Dell Laptop PCs
• Identify Speakers Emitting Unwanted Noise