So I recently bought some Noctua fans. (1 x 120 mm and 2 x 140 mm) for replacement of the stock front and exhaust fans I had.
They work great when it comes to moving air, and they really are nice and silent. BUT the fan speed seems to be very inconsistent at a higher RPM, I suspect it's my incompetence in setting a proper fan curve for them.

I have an Asus Prime B250M Plus Motherboard which does support PWM, and it is turned on in the BIOS. I firstly tuned all the fans using QFan or whatever it's called in the BIOS, but the fan curves it spitted out were utter garbage. I downloaded AI Suite 3 and tuned them again, which yielded a much better result. I like having the fans spin a little faster when gaming and I often monitor my CPU temps using HWMonitor. So I used the AI suites turbo setting and did some minor adjustments to the CPU Fans (Intel Stock cooler) but whenever in this setting, the Noctuas fluctuate in RPM with about 50 - 70 RPM, which is also noticeable.
Fan curve and fan graph
I know the principles of PWM signals, but I don't think it should be this aggressive?
To my untrained eye, these fan curves look fine, but are they too aggressive here?

I built a computer recently and the case fans don’t run a consistent speed. They rev up and then die down and I can’t figure out why.

It’s an ASUS Prime Z790-V motherboard and a Montech Air 903 case.

Any ideas what is going on?

I have the amd stock cooler on my ryzen 5 3600. I can hear a fan running quickly a bit then slowing down for a couple of seconds, its not really that loud but definitely noticeable and a bit annoying. Checked using HWMonitor and the cpu temp (40-50C) + stock cooler speeds are always fluctuating while everything else is more stable. Is this normal? and is there a way to make it more constant? this happens while pc is idle not even while gaming. Also should I download the latest bios for my mobo? (b450 Tomahawk max). Currently using the balanced power plan instead of the ryzen balanced one which did not make a difference

I have a 2 month old build which suddenly became very noisy yesterday, during a fresh startup, under no meaningful load (CPU under 50 degrees). All my fans ( intake, CPU and exhaust) seem to be running at full speed constantly even though the monitoring software shows them running at 50 % or below , situations in which they used to be quiet. Why do I think the fans are running at full speed? The noticeable change in the sound level as well as observing the much longer time they take to fully come to a halt on shutdown (for whatever reason, it is something I have observed when the fans were running normally).

Can anyone advise what could be causing this malfunction in both the PWM controllers as well as the fan speed sensors ?

My pc fans, it might be the amd stock cooler that came with my r7, or the 5 case fans. They run at a very low rpm at idle (i dont know the exact rpm) and then sometimes suddenly jump up every minute or so and run at a higher rpm for about 2-3 seconds before returning to normal. Ive tried tuning the fan curves in the bios and running the diagnostics to no avail.

Hello, I recently build this PC like a week ago. The CPU fan I believe is the cause here, because I can hear it constantly fluctuating in speed. It will do this all day, everyday, no matter if I have only the internet open up. It's not like i'm opening up a demanding video game and it changes speed, no it will change speed back and forth all day long it's kind of weird, even if i'm just watching a youtube video is keeps speeding up and slowing down and I can hear it because it's loud. Any known fix? CPU fan is a hyper 212 air cooler

Hello, I hope I'm not doing anything wrong here since I don't use reddit that often.

Issue: The PCs fan randomly increases the speed to 100% out of nowhere in a moment's notice during gaming-related activities. The quality of the game doesn't seem to matter. So far it occurred in:

-Clair Obscur in a dark cave, even in the menu.
-Wuthering Waves, randomly during combat, particularly during Changli's Ultimate
-Abiotic Factor upon entering the snowman room
-Some other games I sadly can't remember

I wanna clarify, this is a RECENT issue. The PC is prebuilt and about 5-6 years old by now and didn't have any problems up until about 2-3 weeks ago where the first instance happened in Abiotic Factor. Seemingly at random, the fan's speeds go from 1300RPM to 4000+RPM for 2-3 seconds, before dropping down to 1300RPM. This occurs during very specific triggers and although the interval seems to happen at random, it's certainly happens during trackable moments.

The PC is currently freshly dusted, the average temperature lingers between 77-84° C during gaming on High to Epic settings and all fans run smoothly and without any issues outside of those random moments. 99% of the time it's the GPU fan exclusively, sometimes it's "louder" and I presume it's the case fans too, but I couldn't identify that yet as it happens very rarily.

I'm running Win11, 32GB RAM, Intel I9-11900F, an Nvidia Geforce RTX 3070TI, on an Z590 Plus and all drivers are updated.

If anyone could help me fix this, I'd be seriously grateful! I have no clue what's causing this.

Today I first noticed that my laptop fan is not working like it should. Usually while browsing the web the fan is constantly on and silently humming, while playing games the fan is turning very fast. Now while browsing the web the fan is almost turned off and every few minutes the fan starts screaming for a few seconds before turning off again. Speedfan doesn't show me the fan's RPM but the CPU temperature is 60-70 even while not running any programs. The laptop gets very hot and then is cooled down again. It may have started after a windows update i did a few days ago, but I only noticed it today.

I have a Dell 3521(not sure), CPU is Intel i3 3217U, 4gb DDR3, Radeon HD 8750M, Win 8 64bit.

How can I get the fan to cool the laptop consistently?

So, i'm having this weird issue where whenever i turn my pc on my fans go nuts, the speed varries in intervals of 2 seconds between i'm guessing aroung 20% and around 80% until windows fully loads and fan control app takes control of them. the weird thing is, in bios, all fans are set to silent curve, i have tried manually lowering the curve to like 5% until 80 degrees celsius, the speed is set to pwm on all of them. i have 8 bequiet fans, some hooked to the bequiet case controller, some connected trough pwm splitters, some just connected straight to the motherboard. initially i was thinking that it might be a controller/fan/splitter issue but as soon as fan control loads and takes control of them they work just fine. what i want is for the fans to stay at least at a constand 20 to 30% speed until windows fully loads but i'm not sure how i can do that. until recently fans were going straight to 100% and staying there until windows loaded no matter what curve or settings i put into bios fan settings. i'm really confused as to how i'm supposed to fix this damn thing. as a motherboard i have a gigabyte b550 elite v2 rev 1.5

Can anyone help me out and tell me the correct speed my fans should be on my PC. It's a gaming PC with a rtx 3080 and it usually sits between 70 to 80 degrees whilst gaming. My fan speed is at 80% only when it reaches 80 degrees (default setting). Is this correct or should it be higher / lower?

Initially this rear fan (Arctic P12) was an exhaust until I thought my 7800X3D would appreciate extra cooling if I switched to intake. Ever since then, the fan starts making a weird humming noise when it reaches around 40% and above of its rpm. I used Fan Control app to test each case fan by setting to 100%, and this fan is the only one that creates the noise. Should I just set to constant rpm, or are there any other solutions?

Case fans, cpu heat sink fans, radiator fans, etc…

How many fans does your system have and how do you control the speed of them all? I’m looking for ideas…