Computer fans keep speeding up and slowing down?

[phomatic]

My computer is really new, something like 3 months or so, and it's a high-end computer, but something with the fans is wrong I think.

It's fairly recent that this has been happening, but essentially it sounds like fans (I think it's the fans?) keep revving up and then slowing down. It's like it's happening when I'm just browsing the internet, not even playing games. It happens every 5-10 seconds or so and then dies down or keeps going and then repeats.

Any ideas on what to do or why this is happening? I assume it's not the greatest for my pc to continue to do this every day.

Also, I have MSI Afterburner and the "Fan Speed" isn't changing as it's on auto and at 43 when this is happening. So I know it's not my graphics card fans.

 

[skywalkerqq]

go into your motherboards bios and change the fan curves

they are probably doing this because they are set on the default curve

 

[modobiker]

What is your system spec? I had this kind of issue with a MSI x370 Krait Gaming MB. I tried changing the fan curves settings but it looked like the MB and CPU CoolerMaster cooler were not matching signals, thus it kept revving up and down while idle. I "solved" by setting a constant speed under BIOS menu.

 

[Paperdoc]

This is not a big technical problem, but it can be annoying. First, why is it happening?

The normal operation of the mobo's automatic fan speed control system manipulates the fan speeds according to TEMPERATURES measured in the CPU and on the mobo. As a temperature rises, the system speeds up the associated fan to remove heat, and that normally causes the temperature to stabilize or even to fall back a bit. The method the system uses to change fan speeds is not a slow continuous one; instead, it tends to jump in modest steps from one speed to another. In your case, OP, it just happens that the "normal" operating temperature for the workload you do is right at a point where one of your fan control systems want to jump the speed up. But that causes the temperature to drop a little, so the system slows it down again. The just keeps going on. It is not a symptom of a problem and not really a source of damage to anything. But it is annoying.

What to do? Skywalkerqq has the right idea. See if you can find on the CD that came with your mobo a utility that runs under Windows so you can see it during real normal work and that allows you to observe and adjust various system parameters, including the way the fans are managed. Look at both the CPU fan and the CHA_FAN or SYS_FAN speeds. One or both will be jumping up and down slowly, in time with the sounds you hear. That is the fan configuration you want to adjust.

Most fan headers offer you about four choices of control "profile": normal automatic, fixed full speed, fixed slower speed, or a custom "manual fan curve". Choose the latter and observe how it is set already. Note in that curve about where your system is operating now in terms of temperature and fan speed. Basically you want to change that area of the control curve setting so that the jump from one speed to another is at a different temperature - slightly lower or higher. You may have to confirm your change to make it permanent. This should make the system stop cycling up and down as long as your typical workload remains the same as it has been.