PC Components

Do PSU Fans Always Spin? (8 Things You Need To Know)

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Many users are confused about when their Power Supply fan spins and when it doesn’t spin; if you are also confused about this issue, then you are in the right place.

I did a ton of research about when the PSU fan spins and when it doesn’t spin, and after doing the complete analysis, I am writing this article to give the appropriate answer to your question.

Generally, a PSU fan doesn’t always spin; when the fan will spin that depends on many factors, including the loading inside the PC systems. 

When Does PSU Fan Start To Spin?

The Power Supply fan starts spinning under a significant load. It will automatically begin to spinning when it warms up or when the load is high enough. 

Usually, the PSU fans are thermally controlled, and that’s why they won’t turn on until it has to. According to some experts, the fan will not spin unless there is a 30% load on the PSU and until there is a 50C-60C temperature.

For instance, if you use a 750W Power Supply, the fan will not spin until your PC consumes 250W to 300W.

At low loads, the Power Supply fan stays at Zero RPM Fan Mode; hence it does its tasks silently; therefore, you won’t be able to hear the sound. To learn more about how to check PSU speed and sound, read this article.

PSU Fan Alway Spinning

PSU fan starts spinning when there is a sufficient load inside the PC system, but this fact might not apply to all the PSUs.

If you have a low-budget PSU, then there might not be any passive fan control, and in this instance, your PSU fan should spin when you provide power to the PC system. 

So, if you have a cheap power supply and the fan is spinning continuously, there is no need to worry about that, but if the PSU fan is spinning rapidly, it means you have reached the maximum capacity.

There are a couple of things that you can do to fix this issue- The first thing you can do is clean the dust; secondly, you can reduce the power consumption of the Power Supply, You can also update the BIOS versions, and finally, you should check the PC ventilation holes whether there any blockage or not.

My PSU Fan is Not Spinning

Many people face such issues that their Power Supply fan is not spinning; sometimes, there can be some serious issues, while sometimes, it can just be a misunderstanding.

You first need to figure out if the fan is intended to spin on startup or not. Some Power Supplies have a temperature control fan which means it will not start unless the PSU is not getting too warm.

Moreover, if you have an older PSU and you are facing similar issues, something may be wrong, and in that case, you need an initial check to see whether the fan is working correctly.

While checking the fan, you have to spin the fan; if it takes force to spin it or the fan instantly stops, the fan bearings may be full of dust.

Also other reasons can cause this similar issue, and some of these reasons are explained below.

Why is PSU Fan Not Spinning?

Let’s explore some crucial reasons behind why the Power Supply fan is not spinning-

Semi-Passive Cooling (Zero RPM Mode)

Nowadays, some PSUs offer a semi-passive cooling mode, also known as the zero RPM mode. In this mode, the PSU fan doesn’t spin until there are enough temperatures.

When the PSU temperature increase, the PSU fan will start spinning unless the fan will not spin. So, just figure out whether your PSU had zero RPM mode or not and also figure out how much load your PSU requires because some PSU fan spins at 15% load, some spin at 20% load, while some PSU fan spins at 50% load.

Fan Issues

If you buy a Power Supply from an unreputed brand, then there is a chance that the PSU fan has some significant issues. Sometimes the PSU fan stops working due to the accumulation of dust particles inside the PSU system, while sometimes, major hardware failures can also damage the PSU fan.

So, if there are dust particles, then clear that out and see whether the fan is now working correctly or not. But the better option would be to replace the fan of the Power Supply with a new one.

PSU Internal Damages

A Power Supply has several integral parts inside it like a transformer, rectifier, filters, circuits, capacitors, and resistors; any of these components’ failure can stop the PSU fan from working correctly.

Loose Connection

If there is a loose connection on the PSU fan connector to the two-pin header, then the PSU fan will not spin, so check out the connection.

These are some of the issues that can severely damage your PSU fan. So, just check all these reasons one by one to see which problem is causing the Power supply fan issues.

What To Do If PSU Fan is Not Spinning?

If your Power Supply fan is not spinning, then replacing that old power supply fan with a new one is preferable.

But before replacing the fan, you have to check a couple of things, and here I have mentioned all of those things. So, let’s check that out-.

  • Check Out whether it is the semi-passive cooling mode PSU fan or not.
  • Secondly, check whether the PC load is around 30% to 50% because some PSUs don’t spin at low loads.
  • Check out whether there are accumulated dust particles and if there is dust, then clean it.
  • Check whether there are loose cable connections or not.

After checking all these factors, if you notice that the PSU fan is not spinning, then replace the PSU with a new one. If you are confused about how powerful a PSU you need, then read this.

Should PSU Fan Turn on Immediately When It is PLugged in?

The modern PSU fan doesn’t turn on immediately when it is plugged in, and it starts spinning when there is a sufficient load inside the PSU. 

In short, the PSU fan does not spin until there is PSU that delivers enough power to the computer and all its devices that it generates heat inside the PSU itself. So, even if you switch it on, the PSU fan may not spin because it does so little work.

PSU Fan Not Spinning on Startup

If your power supply fan is not spinning on startup, you must stop the system and disconnect the Power Supply from the power source.

Now, do an experiment to determine whether the fan is spinning freely or not. To do this experiment, simply stick a stiff wire through the mesh & give the fan blade a small nudge.

Now, it should easily spin at least a half turn if it is free spinning. If it doesn’t move freely, then the fan has failed. If that is the case, you must replace your old Power Supply with a new one.

But if you have a modern Power Supply, the fan may be thermostatically controlled and will only turn on under load. The fan may never turn on if your load is light and your place has air conditioning. So, if you have a modern Power Supply, check it out before replacing it.

Power Supply Fan Spinning Too Fast

The power supply fan sometimes spins so fast, especially if the fan is directly connected to the PSU through a Molex fan connector. So we can diagnose the reason to troubleshoot this problem.

The dust particles, Outdated BIOS version, old Power Supply, and bad ventilation issues can spin the PSU fan quickly. In this matter, you have to diagnose the cause appropriately and then resolve it.

Moreover, if the PSU fan fails due to hardware failures, then the only way to resolve this problem is by replacing the fan with a new one.

Final Verdict

Based on all the factors, it’s clear that the PSU fan doesn’t always spin; instead, it spins when there is sufficient load inside the system. Some fan starts spinning at 30% load, while some PSU fan starts spinning at 50% load.

I hope the article clears all your doubts and if you want to know more about the Power Supply, PSU fans, motherboards, storage components, CPU, GPU, etc., follow this blog regularly.

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