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High Pitched Noise Emanating from the Notebook PC

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Support details

Problem Description

A high pitched noise may emanate from the notebook PC. The noise is caused by the CPU going into a lower power state to conserve battery power. If the sound is fairly quiet and does not bother you, no action is needed. However, if the sound does bother you, download and install an updated BIOS, and then configure the CPU setting to resolve this problem.

WARNING:

Apply this solution only to a notebook PC with an Intel processor. Attempting to install this update to a PC with a non-Intel processor will cause a serious error.

Determine type of notebook processor

Notebook PCs use processors from different manufacturers. To determine the type of processor in your PC, press the FN and Esc keys at the same time, to open the System Information window. The processor name and System BIOS information is displayed.

Alternately, click Start , right-click Computer , and select Properties to open the System window.

Update BIOS

To update the Intel BIOS perform the following steps:

Download and install BIOS version F.16 (SP34782).

Softpaq Description	Information	Download
WinFlash for HP Notebook System BIOS (for Notebooks with Intel Processors) - Microsoft Windows/Vista-Based, VERSION: F.16	SP34782 Instructions/Information	SP34782 File Download

After updating the BIOS, reboot the PC and press F10 when the HP logo displays to enter BIOS setup.
Use the Left/Right arrow keys to select System Configuration .
Use the Up/Down arrow keys to select CPU C4 Function and press Enter .
Use the Up/Down arrow keys to select the option to DISABLE the CPU C4 Function , and then press Enter .
Disabling the C4 function will prevent the notebook from going into the low power state, will cause the CPU fan to run more frequently, and will reduce the battery charge capacity.
Press F10 and then press Enter to accept the change and exit the BIOS setup.

If the sound is fairly quiet and does not bother you, accept the default ENABLE setting to allow the notebook to go into the reduced power C4 state.