A quiet computer that suddenly starts humming, whistling or ticking is telling you something. Sometimes it's a harmless annoyance, sometimes it's the early warning of a failure. The good news is that noises, listened to with a little method, are among the easiest symptoms to interpret: each component has its own "voice", and isolating it is almost always enough to tell who's speaking.
First rule: locate the source
Before doing anything, you need to know where the sound comes from. A few simple techniques:
- listen with the case open, with the PC on and with care, bringing your ear close to the different areas: power supply, graphics card, processor cooler, drives, case fans;
- use a cardboard tube as a stethoscope: placed near a component, it isolates the sound very well;
- correlate the noise with the load: does it appear at startup, during games, when copying files, or is it constant?
- stop a fan for an instant with a finger on the central hub, never on the blades: if the noise disappears, you've found the source. Do it for a few seconds only and mind the cables.
Fans
They are the most common cause. Typical sounds:
| Noise | Likely cause | Remedy |
|---|---|---|
| Loud, constant whoosh | fans at high speed, dust on heatsinks | cleaning, gentler fan curves |
| Hum that rises and falls | speed oscillating due to an overly twitchy curve | add hysteresis or delay to the curve |
| Scraping or ticking | a cable or object touching the blades | tidy the cables, cable ties |
| Rough hum, worse at startup | worn bearing | replace the fan |
A fan with a worn bearing can often be recognised because the noise is louder when cold and fades as it warms up, or changes if you tilt the PC. Lubricating it may give temporary relief, but the lasting fix is replacement: fans are cheap, standardised components, as long as you match the size and connector type.
On graphics cards, fans are often proprietary. Many models have a fan-stop mode below a certain load: if you hear a click followed by a whoosh when you start gaming, it's probably just the fans spinning up.
Coil whine
It's a high-pitched whistle, sometimes an electrical buzz, that changes with the load. It comes from the coils in the power circuits of the graphics card, the motherboard or the power supply: the currents flowing through them make them vibrate just audibly.
Typical signs:
- it's most noticeable at very high frame rates, for example in game menus;
- it varies with what's happening on screen;
- there's no sign of malfunction.
In the vast majority of cases, coil whine is not a fault and doesn't shorten the component's life. You can reduce it by capping frames per second, enabling vertical sync or the monitor's variable refresh rate, or slightly lowering the graphics card's power limit. If it's very loud and the product is new, it may be worth asking for a warranty replacement.
The hard disk
Mechanical hard disks make normal noises: a slight spinning whoosh and the crackle of the heads during reads. These are different from the worrying ones:
- rhythmic, repeated clicking, often followed by the motor spinning up again: the head can't read and returns to its parking position. It's a serious sign;
- scraping or screeching: possible contact between head and platter;
- humming without spinning: the motor can't start.
Faced with these sounds there's only one rule: switch off and don't insist. Every attempt to restart can make the damage worse. If the data has no backup, the right path is a data recovery service, not home experiments. If the drive is still readable, the priority is to copy the important files straight away, before any lengthy diagnosis.
SSDs, on the other hand, have no moving parts and make no noise: an SSD that "makes noise" is almost always actually another component.
Vibrations and resonance
A low hum that changes when you touch the side panel or move the PC is a mechanical vibration: a hard disk making the drive cage resonate, a panel not screwed down properly, the case sitting on a piece of furniture that acts as a sound box. It's solved with anti-vibration mounts for the drives, by tightening the panel screws, or by putting the PC on a more rigid surface or on rubber feet.
The power supply
A quality power supply is almost silent at low load. A constant electrical buzz, ticking or, worse, a burning smell are signs not to ignore. The power supply must never be opened: the capacitors inside can hold dangerous voltages even when unplugged. If it's suspect, it gets replaced.
A three-step method
In my work I approach every noise like this: first I locate it, then I check when it appears, and finally I see whether it comes with other symptoms, such as abnormal temperatures, SMART errors or instability. A noise without other symptoms is often an annoyance to reduce; a noise accompanied by other signs is a fault to deal with right away.
In short
- Locate the source before acting: your ear, a cardboard tube, fans stopped for an instant.
- Noisy fans: dust, cables in the blades or worn bearings to replace.
- Coil whine is annoying but usually harmless; capping frame rates reduces it.
- Repeated hard disk clicks: switch off, don't insist and secure the data.
- Never open the power supply: if it makes abnormal noises, replace it.
