Dirty case fans are the most common cause of computer buzzing noises. Unfortunately, the fans gather dust with time, and eventually, it becomes more difficult for the fans to cool your desktop or laptop.

As a result, it starts to spin faster, creating a mild buzzing or whirring sound.

Similarly, if the PC case or laptop doesn’t have adequate airflow, an overworking and loud fan will result. 

This most commonly happens when you place your laptop directly on your bed or a pillow.

The same is true when PC cases are placed flush with a surface, especially if fan vents are located nearby.

How to fix

The best way to clean dusty fans is simply by passing a dust blower or electric duster over them.

Avoid using a hairdryer (unless it has a ‘cool’ setting) because hot air can cause damage to the internal hardware.

Also, if you’re tech-savvy enough, you might want to unscrew your system and manually wipe off the dust.

This is best done using a microfiber cloth and gentle pressure. The fans are made of plastic and can easily bend or break.

Other than this, it’s also advised to give the fans adequate space for clean airflow. To do this, use a laptop stand instead of placing it on top of your bed or a pillow.

Be sure to keep at least 4-inches of gap between your PC tower’s fan vents and any surface like a wall or table.

Take note of your computer’s case fans. Whether or not you hear buzzing noises, you should keep them clean.

Dirt and dust inside your PC can lead to much more severe issues if left to build up for long periods.

If the fan is still noisy after giving it a good clean, you need to replace it with a new one.

Here are my recommended replacement fans (Links go to Amazon):

2. Loose screws and wires

Loose screws and wires/cables are generally more common with desktops. This issue usually won’t happen in laptops unless it’s recently been taken apart for an upgrade or repair.

Occasionally, a loose cable gets close to one of the fans. It then gets repeatedly hit by the fan blades, creating a buzzing or rapid clicking noise.

On a similar note, a loose screw can misalign the structure of the casing, which, in turn, may slightly dislodge the fans.

If a fan isn’t spinning in place, it can vibrate against the surrounding components and create a subtle rattling or buzzing noise.

How to fix

To fix loose cables, open your computer, move the cables away from your fans, and secure them, so they don’t fall back again.

To fix loose screws, simply tightening them should suffice. Make sure to properly align the casing beforehand, if necessary.

Notably, this is comparatively easier on desktops than laptops. Furthermore, tampering with the laptop internals by yourself can void the warranty.

For these reasons, I recommend getting a laptop checked out by a technician if you think there’s a loose wire inside.

3. Damaged DVD/CD-ROM

DVD/CD-ROMs create a subtle buzzing noise while in use. This happens because the CD or DVD placed inside spins at high speeds as the device reads it.

Generally, this noise isn’t overly loud or annoying. However, if the device is damaged, it can lead to very noticeable buzzing and crackling noises. 

Other than this, a DVD/CD-ROM can also start rumbling if dust particles get lodged inside or if a cracked or heavily scratched-up DVD/CD is inserted.

How to fix

Here’s how to fix a damaged DVD/CD-ROM:

1. Open the DVD/CD-ROM and use a dust blower to clean it.
2. Take out any DVDs or CDs you had inside and check for scratches or cracks. If present, discontinue use and discard the disk. If it’s intact, use a microfiber cloth to clean the disk and remove any dust particles.
3. Re-insert the cleaned disc back into the device to check if it’s still making noises. If yes, the device is likely damaged, and a repair or replacement will be required. 

However, it should be noted if you notice the buzzing noise coming from the device when no disk has been inserted, it’s best to call in a technician.

4. Failing hard disk drives

A hard disk drive (HDD) working normally can produce a low hum or clicking noise. This is because there are a lot of components inside an HDD moving at high speeds. 

However, if these components get worn out or come in contact with each other, an audible buzzing, whizzing, or grinding sound may be produced. You might even hear periodic thuds. 

These sounds are essentially warning signs the HDD is failing, which can happen anywhere from a few minutes to a few months.

Since it’s hard to tell precisely when this may occur, it’s highly recommended to backup your data and get the drive replaced.

How to fix

If your HDD is failing, there isn’t much you can do to fix it.

Your only options are to back up the data to a new and working HDD, or preferably an SSD (Solid State Drive), which doesn’t have any moving parts and has better longevity than HDDs.

But how can you determine if it’s the HDD that’s damaged just by the buzzing noise from your computer? 

A failing HDD also comes with other problems like slow read and write speeds. You might also notice some files on your drive got corrupted (not opening).

Here’s a helpful 7-min YouTube video on how to tell if your HDD is failing from NCIX Tech Tips:
https://www.youtube.com/watch?v=TETQ_oCJgFI

5. CPU Overload

If you only notice the loud buzzing noise when playing graphics-intensive games or editing 4k videos, then it’s likely due to CPU overload.

Tip: Make sure you have a good quality CPU cooler installed and the thermal paste is relatively fresh, so you can be confident that the overheating CPU isn’t the result of an inadequate cooler or older thermal paste.

The CPU gets hot when it performs CPU-intensive tasks, which puts the fans on overdrive to cool down the system.

As a result, the high-speed fans produce an audible buzzing noise. This can be annoying, but it’s completely natural.

You might also notice the noise when opening a particular program, albeit a low resource-intensive one.

In that case, a bug or virus within the particular app triggering high CPU usage could be to blame.

How to fix

To determine whether the noise results from high CPU usage and then fix it, follow these steps:

1. Open the Task Manager on Windows by pressing Ctrl+Shift+Esc; On Mac, Go to Applications>Utilities and open the Activity Monitor.
2. Check the list of all running apps and processes on your system to see if a particular app or process is pushing your CPU usage. If yes, then you have found your culprit.
3. If it’s not something you use, just kill the app. However, if you do use the app, ensure other programs aren’t running when it’s in use. That way, you’ll free up your CPU resources and dedicate them to one app, which can reduce the overall stress.

Another thing to remember is certain malware can cause high-CPU usage. If you suspect the system is infected, use anti-virus software to find and remove the malware.

6. Coil whine

Coil whine refers to an electromagnetic phenomenon where coils inside particular electronic components start to vibrate at just the right frequency to produce an audible and annoying whining noise – hence the name.

In computers, coil whine is mainly associated with GPUs when they are under high stress from either playing demanding games or editing 4k videos.

Another common source for coil whine is from power adapters used to charge laptops or deliver power to large monitors. It’s most common with older devices that use power bricks.

To get a technical understanding of coil whine, check out this 5-min YouTube video from Techquickie:
https://www.youtube.com/watch?v=T7HsXHqtxrI
How to fix

The unfortunate thing about coil whine is that there’s not much you can do about it once you have it.

Furthermore, most manufacturers don’t offer a warranty for coil whine, so it can’t be replaced either.

As such, if you notice the noise is coming from your GPU, I recommend trying not to stress about it too much.

And while you’re playing the graphically intensive titles, wear an ANC (Active Noise Cancellation) headset to drown out the noise.

If the coil whine is coming from the power adapter, move it as far away as possible from your device to reduce the noise.

Be sure not to cover up the power adapter and dampen the noise, as this could lead to overheating and even potential explosions.

Since there’s no fix for coil whine, the best way to avoid it is by purchasing components unsusceptible to it.

As such, it’s imperative to read user reviews before buying new hardware to see if other users are complaining about noise levels.

7. Overworked power supply

Power supplies or PSUs are in charge of delivering power to the various components of your desktop PCs. Laptops don’t have PSUs and don’t face problems related to them.

Now, if your CPU or GPU is demanding more power, the PSU needs to work harder, which can cause excess heat generation.

This is why all modern PSUs come equipped with dedicated fans to cool the device. 

These fans can create an audible buzzing noise if the PSU is under load. The same thing can happen if the fans become dusty or if the path for airflow is obstructed.

How to fix

The first thing to do is verify the PSU has a high enough wattage rating to meet the power demands of the different components of your PC, including CPU, GPU, monitor, etc.

If not, it’s best to get a new PSU with a higher wattage rating.

Also, PSU fans will gather dust over time, so you should make a schedule to clean it at least twice a year.

After that, a few simple sweeps from a dust blower or electric duster should do the trick.

Finally, avoid positioning your PC so that the PSU fans don’t have any room for airflow. Instead, keep it at least a few inches away from any surface.

Key takeaways

Buzzing noises from your computer can originate from dusty case fans, loose cables hitting other parts, damaged DVD/CD-ROMs, failing HDDs, coil whine, high CPU usage, as well as overloaded PSUs.

To reduce this noise, keep the fans clean and avoid obstructing the airflow. Also, reduce the CPU load by killing unwanted apps and checking for malware.

Use a PSU with a high enough wattage adequate for your PC.

However, if you still notice the buzzing noise after applying these fixes, some components are probably damaged or faulty, and you need to repair or replace them.