Why Does a Computer Motherboard Make a High Pitched Sound?

A single, split-second high-pitched beep is normal for some motherboard models: the sound indicates that the system is ready to boot. Other motherboard beeps, which vary in pitch within the human singing voice range, are used to identify hardware problems with the device. If the motherboard won't turn on correctly, there's no way to view the error code on the screen, so the beep sound functions to tell someone trying to fix the computer what the problem is. Motherboard beeps are clearly audible and frequently use syncopated pulsing patterns. The beeps will stop if the computer is able to load the operating system.

A loose inductor can create a very high-pitched noise that's difficult for many people to even hear. Indicators are usually anchored on the motherboard and create micro-vibrations as a part of their normal use. However, if the inductor comes loose from the motherboard it may start vibrating ever so slightly -- but incredibly quickly -- such that it produces a high-pitched noised similar to the ringing someone hears in their ears following a very loud noise. Inductors are used on the motherboard to prevent irregularities in the electrical current from damaging other hardware components. A loose capacitor won't damage the system, but people who can hear it might find it annoying.

Failing capacitors make an indistinguishably similar noise to loose inductors: an extremely high-pitched ringing noise. Unlike loose inductors, failing capacitors are a serious problem for motherboards: if they go, the motherboard will have a difficult, if not impossible, time operating. If you open the computer and look at the motherboard, failing capacitors may appear to be bulging out of place. The motherboard will need to be repaired or replaced if a capacitor fails; it's usually a wash with the price because of the cost of labor to repair the device.

When a fan starts to fail, it makes a high-pitched squealing noise. Some motherboards with built-in graphics cards and high-end northbridge chips come with installed fans. However, the majority of the fans in the computer are not connected to the motherboard and are more likely to be the cause of the high-pitched noise: many are so close to the motherboard it may be difficult to pin down the exact source of the noise. If a motherboard fan is failing, it should be replaced as soon as possible to prevent the part it cools from overheating and breaking.