Why Is My Power Supply Fan So Loud?

The power supply unit is one of the most important components of a PC. It supplies power to all the other parts of the system so they can do their job right. When you have a problem with it, you should never ignore it because the health of every other component depends on it. 

Why Is My PSU Fan So Loud?

1. Your PC Has Poor Airflow

Proper airflow is essential for a modern-day PC, especially if you intend to do anything resource-intensive on said PC. 

See, hardware components such as CPUs and GPUs consume a lot of power. Most CPUs consume 60 to 100 watts, whereas most GPUs consume upwards of 100 watts. 

The best GPUs today easily soak up several hundred watts of power alone. 

All of this energy is converted into heat. A constant intake of cool air and hot air exit is the only way to prevent this heat from building up within a PC and frying the internals. 

Your power supply needs to keep itself (and the rest of the computer) cool, so if it heats up, it will instruct its fan to spin faster, which results in a loud whirring noise

Here are some of the more common things that can cause your PC to have poor airflow. 

Dust Build Up

Someone uses a vacuum cleaner to suck out the dust inside a computer PSU.

Your PC case is pretty good at keeping dust at bay. Still, it will need a thorough cleaning now and then. Dust will build up in even the most well-ventilated PCs. 

Dust is a pretty good heat insulator, so it will cause heat to remain trapped within your PC casing.

If it gathers on openings, ducts, and air vents, it will cause the inside of your PC to heat up by preventing the hot air from escaping. 

If it gathers on the internal fans of your PC, it will slow them down, further hampering internal airflow and external air exchange. 

The power supply fan will reactively spin faster to improve cooling and eliminate excess heat from your PC. 

As a result, you’ll have to deal with a lot more noise. How much of a problem depends on how inconvenient the noise is, as most PCs can regulate their internal temperatures by making the fans spin faster. 

If the resulting noise is uncomfortably loud, you should open up your PC’s casing and get rid of the dust inside with a can of compressed air. 

You can also use a hair dryer, as long as you remember, not letting the internals of the PC come into direct physical contact with the dryer, as this could cause a build-up of static electricity, which can fry electronic components. 

Caked dust you’ll have to remove with manual force. You can douse your cleaning material in isopropyl alcohol to make the dust come off easier. 

Unsuitable Positioning

If your PC has its back turned to a wall that it’s very close to, air won’t be able to escape as effectively through the back vents. This is problematic and will lead to a heat build-up within the PC. 

Keeping your PC in a drawer or closet may give you a tidier workspace, but it’s a surefire way to cut off years of the system’s lifespan. 

Ensure your PC’s immediate surroundings are clear and conducive to proper airflow. Avoid keeping your PC in enclosed spaces. 

No Air Intake

Most PCs have reliable air exhaust, but many still have poor air intake today. Unfortunately, you need both to have good airflow. One won’t work without the other. 

Modern PC casings often come with a set of built-in fans for intake and exhaust, so you don’t have to worry as much about airflow if you have one of those.

But it’s still a good idea to check the airflow configuration just in case something wasn’t supplied in the proper intended order. 

If you have an older, standard PC casing that looks like it belongs in an office, you may have to install internal fans to drive airflow. PC fans are compact, inexpensive, and connect to the motherboard directly. 

2. Incorrect Power Supply Orientation

The power supply air intake fan orientation is demonstrated.

The orientation of your power supply inside the casing matters. Your PSU fan should not be a major driver of airflow, so it needs to work in isolation instead of working with the rest of the system’s airflow.

The visible fan on most power supply units is an intake fan. The air is expelled through vents on an adjacent face. 

Some people think the power supply can help keep the inside of a PC cooler. However, your PSU fan should never be facing upwards.

If it is, it will draw in hot air from inside the PC and blow it onto the components. It is meant to cool and pass even hotter air out the exit vents. Resulting in the power supply rising in temperature even quicker.

The power supply airflow rate isn’t great, so it shouldn’t be used as an exhaust mechanism for hot air inside the case.  

The fan should be placed downward to keep only your power supply cooler. That way, it will draw cool air from the outside.

This only works if your PC case has enough ground clearance and a bottom opening for the air to come through. Most modern cases do, but many older cases don’t. 

If you’re sure your power supply fan is making the noise, it may be worth reorienting your PSU to have its fan face downwards.

It’ll stay cooler that way, which will, in turn, cause the PSU fan to spin slower, reducing noise. 

Always ensure enough air gap under the case so you don’t choke out the power supply’s air intake.

If your computer is standing on a desk, it will most likely be fine, but if your PC is sitting on a carpet or floor, inspect the air gap carefully.

Solutions like adding stilts to the case’s feet or placing your computer case on a board are excellent solutions to allow good air intake for your power supply.

Most modern PC cases have easily removable air intake filters for power supplies. If you maintain the filter, you can ensure it always gets clean and easy-flowing air.

This will also help keep your power fan and internals cleaner for longer.

3. A Fan Bearing Is Worn

Your PSU fan may have a worn bearing if you hear a constant whirring or rattling noise. It can sometimes only be present in the first few minutes of being powered on.

Remove your PC case and examine your PSU fan while operating. If it wobbles, a worn or loose bearing is likely a culprit. 

Now, a worn-out bearing is not a major problem. Other than the annoying noise, it will cause the remaining lifespan of the fan to shorten. 

You cannot fix a loose bearing at home without opening the PSU, which you should not do.

Caution: Opening a PSU is a major safety hazard even when disconnected from power.

If you want to get the PSU fan fixed, I recommend you get it serviced by a professional. Better sooner than later.

Because even though the wobbly fan will still serve its purpose, for the time being, it will likely fail soon. 

And when it does, you’ll have to get it repaired because running a PSU without its fan is extremely dangerous. 

It Hasn’t Been Secured To The Case Correctly

While you’re inspecting the fan health, also check the PSU itself. Remember to disconnect the power before handling the PSU. 

Make sure it’s secured to the PC case firmly. A loose nut or bolt could cause the entire unit to wobble because of the fan movement. 

4. Your Power Supply Is Inadequate

All PSUs have a maximum power limit they can supply to your computer.

For most, this value is somewhere between 300 watts to 1000 watts. You’ll find outliers, but those supplies are used in niche cases. 

An office computer, for example, can operate just fine with a 300-watt power supply.

Even a 600-watt supply might be insufficient for a gaming PC, especially considering the monstrous cards GPU companies have been producing lately. 

Alright, so why is this important?

You don’t want your power supply to run at its maximum capacity.

It’s important to have some gap between your system’s total power consumption and the maximum capacity to prevent overheating. 

  • A PSU running at 100% will no doubt heat up, which will cause its fan to spin faster to try and cool it down. 
  • You won’t be able to harness the full processing power of your system due to a lack of power to the components. 

The power supply will likely suit the components if you buy a prebuilt PC. However, if you recently swapped something out or added something new to the PC, you may have exceeded its capacity. 

Since the GPU tends to be the most power-hungry component in your average PC, GPU power consumption determines the PSU you’ll need. 

For example, the ideal power supply for a computer with a 100-watt rated GPU would be able to supply the system with 300 to 400 watts. 

For a 400-watt GPU, the ideal power supply would be capable of providing 700 to 800 watts. 

There is some guesswork involved in determining which PSU is right for your system, but you can always rely on the recommendations of your GPU’s manufacturer. 

If you would like to know more, please read my article explaining how many Watts should a gaming PC have.

The Power Supply Has Poor Energy Efficiency

There is another aspect to them called the efficiency rating. It’ll be easier to explain with an example. 

Say you have a 600-watt power supply that’s 80% efficient. This PSU will draw 720 watts from the wall socket, convert 20% (120 watts) to heat, and deliver 600 watts to your system under full load. 

Now, imagine a similar scenario but with a PSU that’s 60% efficient (600 watts without the 80+). It would draw 840 watts from the socket, turn 40% (240 watts) into heat energy, and deliver 600 watts to your system under full load. 

Not only does the latter draw more power and waste more energy, but it also produces twice the heat. 

Most power supplies today are rated, at minimum, 80+ bronze. The best PSUs of 80+ Titanium have efficiencies as high as 90%. 

If you have an older one without an 80+ rating, it’s likely converting too much power into heat and then having to run its fan at high speeds to compensate.

I recommend switching to a newer PSU with an 80+ efficiency rating. Not only will it run much quieter, but you’ll also save energy. 

5. It’s Another Component

Lastly, the loud noise may not come from your power supply fan. Inside your PC are several fans:

  • The CPU stock/dedicated cooler. 
  • The GPU fans. Most modern GPUs have two or three cooling fans attached to their heatsink. 
  • Any other internal fans or RGB fans. 

Any one of these fans could be producing the noise. The most likely culprit is the GPU. 

As I mentioned earlier, the GPU is the most power-hungry component in your average system. It is, therefore, the component that produces the most heat and needs the most effective cooling solution. 

GPU fans tend to spin much faster than the other fans I’ve mentioned above, especially when the chip is overloaded from running a game or rendering an animation, etc. 

My point is that before you write off the noise as a power supply fan issue, check the health of the GPU fans. 

6. The Power Supply Is Faulty

Lastly, if you’ve come this far without discovering why your power supply fan is so loud, it may be faulty.

In this case, the best thing to do is to get the unit serviced by a professional. They’ll be able to repair it or help you get a new one. 

You cannot fix a faulty power supply at home. You should never open it. The capacitors inside can store a high charge even after disconnecting the unit from the socket. 

You could get hurt pretty badly.