How To Fix Power Supply Fan Noise

The power supply is arguably the least exciting part of a personal computer. Not surprisingly, it tends to get ignored and often has the least amount of budget allocated in most PC builds. That's also why the Power Supply Unit (PSU) happens to be the culprit in most noisy computers. Here we take a look at the various ways in which your power supply can cause a racket and how to reduce power supply noise on your PC.

1. Is the PSU fan clear?

If the noise emanating from your computer is loud and harsh, your first line of action should be to open the case and verify whether the PSU fan blades are free of obstacles. It isn't uncommon for stray cables to poke into the fan blades despite the protective grill. This is easily fixed by simply securing the object poking into the PSU fan.

However, things get tricky if the source of this obstruction is internal. Resist the temptation to take the power supply apart yourself at all costs. The bulk capacitors within can hold enough electrical potential to kill you even when the device is powered off. Please leave this to the professionals and take the PSU to the authorized service center.

2. Is the PSU fan worn out?

If the harsh/buzzing sounds persist without any sign of obstruction, there's a good chance that the fan bearing has worn out. Older and/or cheaper PSUs employ fans with sleeve-bearing fans that are notorious for making unpleasant noises near the end of their life cycle. The problem can be rectified by either re-lubing the sleeve-bearing fans or outright replacing them. However, this cannot be done without taking the PSU apart. That's something we don't recommend under any circumstance.

3. Check the case mounting screws

This might seem like a no-brainer, but it isn't uncommon for PC builders to either skimp on PSU screws or forget to tighten them. If your PSU isn't secured to the case, the rotating mass of the built-in fan can cause vibrations that are loud enough to be heard. Fixing this is a matter of adding missing screws and/or tightening the loose ones.

4. Check air intake/exhaust for blockage

A PC component that draws in air is usually equipped with mesh filters for dust control. These filtered intakes tend to accumulate dust and become clogged over time. The PSU fan is no exception. In fact, it is quite prone to clogging since it usually takes in air from the bottom of the case. Being placed on the floor doesn't help matters either.

A clogged PSU air intake can cause the fan to run faster and noisier. Clean the PSU fan filter/intake periodically to avoid this problem. Avoid placing the rear of the case too close to a wall or otherwise obstructing the exhaust mesh of the PSU in any way. Failure to do so will contribute to heat buildup and consequently increased fan noise.

5. Keep it off the carpet

This advice isn't restricted to laptops, as it also applies to desktop computers. If you're rocking thick carpets, you must either place the PC case on the desk or use a trolley to elevate it off the ground. Thick carpets can block the PSU fan intake at the bottom and make it noisier.

6. Make sure the PSU is oriented correctly

This is a fairly common mistake committed by novice PC builders and leading technology media houses alike. All desktop PC cases are designed to mount power supplies in a specific orientation for optimal cooling by ensuring air intake and exhaust along the correct direction. Mount the PSU the wrong way, and you risk blocking the critical cooling airflow. This installation error manifests itself as excessive fan noise. It is also a potential fire hazard.

7. Don't rule out coil whine

With all the standard remedies out of the way, here's something from left field. Coil whine can be as noisy as a misbehaving fan and much harder to diagnose. It manifests as a harsh buzzing noise that tends to rise and fall with varying levels of PC activity. Coil whine emanates from inductors or power coils found on the PSU's printed circuit board. This is easily located once you put your ear towards the GPU, motherboard, and PSU to isolate the culprit.

These power-conditioning components tend to vibrate in tandem with high frequency currents coursing through them, thereby making a buzzing sound when the frequency of vibration matches with the inductors' natural resonant frequency. Most well-designed PSUs prevent this annoying phenomenon with better design and having these components coated with vibration/sound-absorbing materials. Reputable PSU manufacturers offer replacements for premium/high-performance units exhibiting excessive coil whine.

8. Running your PSU in the sweet spot

A computer PSU must convert alternating current from a wall outlet into direct current required by the PC components. This AC-to-DC conversion is fraught with inefficiency that is converted to heat. Computer PSUs are the most efficient when they are asked to supply anywhere between 40 and 60 percent of their total rated output.

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The PSU tends to become inefficient when it is forced to supply power outside of this sweet spot. In other words, a PSU rated at 1000 watts isn't efficient enough while supplying 950 watts of power. This inefficiency manifests as heat dissipation through the power-delivery components. That in turn forces the cooling fan to work hard, which consequently contributes to overall noise.

One way is to calculate the amount of power your PC is consuming, then get an oversized PSU. It isn't uncommon for PC builders to choose grossly powerful power supplies. Most power supplies don't switch on the fans until the system load reaches 30 percent of their rated capacity. The solution might not be efficient, but it sure is quiet.

9. Undervolting to keep things quiet

Undervolting is the exact opposite of overclocking. In simple terms, it involves reducing the maximum voltage supplied to critical processing hardware, such as the CPU and the GPU. Refer to our excellent undervolting guide to learn more about the process.

Reducing voltage to these components lowers the total power consumption and therefore the total heat dissipated by the PSU as well. This also makes your computer and PSU run significantly cooler and quieter. This process may be involved, but it is a powerful option if all previous options fail to make your PSU run silently.

Conclusion: it's smarter to invest in a good PSU

While all these remedies will address your problem to some extent, there's little that can be done if you are rocking a really cheap power supply. That's a bad idea because low-quality PSUs are responsible for most system stability issues and critical component failures. It is a good idea to be able to identify a dying power supply. And don't forget to check our guide to choose the correct PSU for your PC.

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Nachiket Mhatre

Growing up, Nachiket had a penchant for disassembling household electronics and appliances; most of which couldn't be reassembled successfully. His parents didn't approve. These days, he leverages his lifelong pursuit of dissecting gadgets to write about technology. His parents still don't approve.