Power Supply Fan Speed

PSU Fan Speed (5 Things You Need To Know)

The Power supply comes with a fan built into the unit, and sometimes users worry that the speed of their PSU fan increases and creates strange sounds.

If you are also facing this difficulty, then you are in the right place because after doing a ton of research about the Power supply fan and its speed, I have written this article to explain everything.

Normal PSU Fan Speed

Generally, the fan speed measured in the RPM unit stands for Rotations per minute. Usually, the fan rotates at a different speed, ensuring the component’s cooling.

The PSU’s fan RPM depends on many crucial factors such as The type of Power supply, the fan installed inside, the temperature inside, and whether the PSU has a thermally controlled fan circuit.

The normal RPM range for some power supplies is between 800 RPM to 1200 RPM. If you want a specific number, then the 1000 RPM will be the typical range for most PSU until they heat up a lot.

When your PSU’s RPM is around 1000, you cannot hear it because whatever noise it makes will extenuate by your CPU and graphics card fan.

Another thing you should consider is that if you have a low-quality PSU from an unknown brand, then the RPM can go up to 2500 to 3000 depending on temps.

Can You Control PSU Fan Speed?

Yes! It’s possible to control the power supply fan speed, but it’s not that simple because its speed depends on the load. The Power Supply fan spins faster when the load increases.

To control the PSU fan speed, you need to determine how fast the PSU fan is running. It isn’t straightforward to decide on this.

To check this, you have to consider different factors, including the temperature inside the units and how long the units are running at a certain temperature.

Even after considering both the factors, it’s difficult to determine the load because the load in computers is dynamic, and therefore the temperature inside the PSU is also dynamic. Often times the temperatures vary from computer to computer.

Many people say that you need the airflow depending on your heat; for instance, 50W of heat is 50W of heat, and you will need the same airflow to dissipate that heat. Therefore the fan should always spin at the same RPM at a particular load. But, it’s not that simple to calculate this.

To know more about these details, I did some experiments where I tested two corsair 600W PSU fans RPM with Intel i7 processor and with mid-range Radeon R9 280X graphics card under equal load.

I did this experiment for 30 minutes, and when the experiment was over, I noticed that the first Corsair PSU fan’s RPM ranged between 850 to 1120. While on the other hand, the 2nd corsair PSU fan’s RPM goes between 720 to 750.

The experiment also tells me that when my CPU temperature increases, the Power supply temperature rises at a similar time. The CPU temperature increases due to several reasons, even a power supply can affect the CPU temp.

Besides the CPU temperature, other factors make the difference in the RPM. And after digging more into this, I realize that both PSU’s fans have the same number of blades, but the difference is in their diameter.

The first Corsair PSU has a slightly smaller fan, around 120mm, whereas the second PSU has a slightly larger size, approximately 140mm. Secondly, my second PSU is 20 mm longer than my first corsair PSU. Thirdly, my 2nd PSU thermistor for fan control is located on the PCB, which is also considered a good thing.

So, it’s clear that besides the CPU temperature, the fan diameter and placement of the thermistor also improve the fan’s RPM.

How To Check PSU Fan Speed?

As I already told you in this article, if you have a PSU whose RPM is around 1000, then it’s impossible to understand that because you will not get any noise from it as this noise will be suppressed by the GPU and CPU cooler sound.

Now, you can use different kinds of software that will tell you the temperature, fan speed, voltage, and many other things.

The Open Hardware Monitor is open-source software that will tell you the temperature, fan speed, voltage clock speed, and other essential things. It is free to use; therefore, you can use it at no cost.

Another option is to use a tachometer (an instrument that measures the rotation speed of a disk, motor, or other components).

How To Control PSU Fan Speed?

Before controlling the PSU fan speed, you need to consider the factors that cause your PSU to run fast. Here I have listed some solutions you can apply if you want to control the PSU fan speed. So, let’s take a look-

  • Clean Out The Dust Inside PSU
  • Watch Your PSU’s power consumption time by time, whether it is reaching the maximum capacity or not.
  • Hear Carefully whether your PSU fan is making some sound; if it’s making some noise, then take the fan out carefully and try to lubricate the bearings.
  • Check out whether there is any blockage in the ventilation or not.
  • Check Out whether there is any BIOS update or not.
  • Finally, If you understand that your PSU fan is damaged, then replace the fan with a new one.

These are some things you can apply to control your Power Supply fan speed.

Power Supply Fan Running Full Speed

If your Power supply fan is running at its full speed and if you hear the sound of the PSU fan, then you should act fast. It might indicate that your Power Supply has some issues and is not working correctly.

Another thing that could happen on the back of the power supply, next to the on/of the switch, there is another switch generally used to change the PSU fan behavior. 

If you accidentally push the button, then it will act differently. So, you have to check this button also.

Final Thoughts

So, after checking all the factors, it’s apparent that load and temperature are the essential factors behind PSU’s high RPM. If you can control these two factors, you can easily control the Power Supply fan speed.

I hope this article is helpful for you and if you want to know more about the Power Supply, CPU, GPU, and other PC components, then follow this blog regularly.


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