I bought my first laptop and the one thing that bothers me about it the fan starts and stops all the time. With normal usage (web browsing) the fan starts for half a minute then the it is silent for half a minute and this cylce is repeated over and over.

Is it normal behavior? Shouldn't the fan blow for longer periods and then stay silent for longer periods? I'm worried about the fan itself if it can take so frequent stops and starts. Is it designed for that? My understanding is it is better for devices to work continuously than start and stop all the time.

What is your experience? Does your laptop fan do the same?

I'm thinking about running some CPU intensive task in the background (like Folding@Home), so that the fan can spin all the time and it doesn't have to stop so frequently.

  • You can try going to Task Manager > Processes > and clicking on "Show processes from all users" then sorting by CPU usage to check if there is a process taking most of CPU. If there is one, see if it is non-essential process that can be turned off and if it is essential one, research if it is normal for that process to take a lot of CPU. – Boris_yo May 3 '12 at 17:03
  • As others have said this is not unsafe but merely bad fan logic choices by the manufacturer. You might have better luck with "Notebook Fan Control" instead of Speedfan, which is designed for desktops. Software fan control is always your-mileage-may-vary. – cloneman Nov 15 '16 at 2:45

The fan is controlled by a thermal sensor.
When the upper edge is reached, the fan starts. It is stopped when the lower threshold is reached by the cooling action.

So, frequent switching of the fan implies you are in a hot environment
(or your laptop vents are not properly ventilated (maybe you are using it on your bed).
The fan will trip on the higher temperatures,
start forcing the temperature down and,
when it sees sufficiently lower temperatures,
will turn off. But, the conditions may push the temperatures high again,
tripping it back into action.

This can also happen frequently when you are doing processor-intensive work.
If your mobile processor supports working at lower power/speed,
the processor intensive activity will push it into higher activity and cause more heating -- which could also trip the fans more often.

Laptop fans are designed to be started and stopped based on sensor data.
I do not think they will get more wear due to that (mine has been working for over 6 years now).
On the contrary, i suspect that a continuous drive might not be very good for the fans life (tho, I am sure there are arguments the other way too).

I think you should not worry too much about the fan.
Meanwhile, you could do something about ventilation and local temperatures to trigger it less often.

Along Jeff's notes, you could also use the SpeedFan app from Almico.

  • I understand that. The question is: Is the fan capable to do so frequent starts and stops without damage? Would it be better for it to run continuously? – Tom Jan 17 '10 at 6:41
  • Temperature is not a problem, it's winter here, so it's not like I live on the tropics or something. :) – Tom Jan 17 '10 at 8:06
  • @Tom, I'd still consider blocked vents critical. But, don't go by just that. Try the apps suggested by Jeff and SpeedFan. – nik Jan 17 '10 at 10:24
  • I don't think blocked vents are causing the problem. The laptop is brand new. It sits on my desk, there is nothing around it to block ventilation. The room temperature is around 23 C and I usually don't do CPU intensive stuff (CPU is around 10-20% mostly), that's why I think the ventillation is excessive, but maybe I'm just inexperienced with laptops. I'll check out SpeedFan. – Tom Jan 17 '10 at 16:57

This can be normal, yes.

It depends on your laptop's BIOS settings and the high and low temperature thresholds to run the fan (typically determined by CPU temperature.)

Have you tried running a CPU temperature monitor app like realtemp or coretemp ? Those work with most modern Intel and AMU CPUs.

There are also fan speed control apps, but they tend to be much more platform specific, depending on the chipset inside your laptop.

You can use CPU-Z to identify your laptop's motherboard chipset, at least..

  • It's a Lenovo G550 and I've seen people complaining about frequent stops: forum.lenovo.com/t5/Lenovo-3000-and-Value-line/G550-fan-problem/… It may be the same problem for me, but not having a laptop before I don't know what fan behavior is considered "normal"? It can also be that I'm simply used to the sound of the constant running of the fan of my old desktop and that's why I notice the frequent stops and starts with the laptop. So I'm not really sure it's normal behvaior I'm not used to, or is it abnormal behavior. – Tom Jan 17 '10 at 8:13
  • 1
    @tom well, many of the default fan speed choices by manufacturers are pretty bad. As nik recommended, I'd look into SpeedFan and see if it is compatible with your motherboard chipset almico.com/sfdownload.php – Jeff Atwood Jan 17 '10 at 8:30

It would help if you define 'all the time'

The reduction in battery consumption is probably enough justification to turn the fan on an off.

By the way, you may be thinking more of purely electronic components which are liable to fail when power cycled, but the fan is a motor (largely a mechanical component) and not susceptible to such problems.

Of course the fan is turned on and off by electronics, but that's not quite the same thing.

  • I use it from AC power 99% of the time. And when I don't do anything CPU heavy (simple browsing) then the fan stops for 30 seconds and then goes on for a while then stops for 30 seconds and so on. I use it in a quiet environment, so it's also kind of bothering, because it's better to have a constant noise level than noise, then deafening silence, then noise again, etc. So the main thing is it gets on my nerves. :) – Tom Jan 17 '10 at 8:44
  • And this is during winter ... it would be interesting to compare the on/off cycle time with a summer pattern, but it doesn't seem to suggest anything's wrong. I can't comment on its effect on your nerves, of course. Maybe you should add some background noise to distract you from the fan noise. It does seems like a good example of the heat management considerations in laptop design and how finely balanced it might be. – pavium Jan 17 '10 at 10:43

If you feel comfortable with installing a new BIOS, try finding a different (newer, older) version of your laptops BIOS and see if the problem is gone. It seems that the temperature points for stopping and/or starting are programmable and a different BIOS sometimes changes that. But be careful, BIOS updates can ruin your computer if done wrong!

Background of my advice: A colleague once (~5 years ago) had a laptop that showed the same frequent stopping and starting that you are describing. It turned out that his computer had a newer (the newest at this time) bios version and when he installed the version we had (an older version), it was gone. Later another BIOS update came out that fixed the problem for him as well.


I have an hp laptop and the fan was starting and stopping, when i changed my settings in power options from hp recommeded to power saver it stopped doing it, now it runs fine in qiet mode and any other setting. i use coolsense to adjust fan speeds.


My computer fan use to speed up to top speed stops and start again in a minute or two. Now my computer tower has two fans one in the back and one inside, the one in the back I clean with the air spray the one on the inside which I never thought to clean was filthy dirty so I clean it with a cotton swabt Q-tip dip in alcohol and presto it stop. So try cleaning the inside fan no need to take it out just use the Q-tip and some alcohol for the hard spots. It work for me

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