I've just answered this somewhere else. Try the settings below. 25C/40 60C/50 65C/80 70C/100 What this does is that, at lower temps, the fans will not ramp up as fast or as intensely, and it will only ramp up upon actual use. There's probably also a ramp up and ramp down speed adjustment. Set it to the highest you can find. Should be 0.7s and 1.0s respectively. Answer from KohGeek on reddit.com
Reddit
reddit.com › r/buildapc › cpu stock fan fluctuating and constantly changing speeds on new pc
r/buildapc on Reddit: cpu stock fan fluctuating and constantly changing speeds on new PC
December 27, 2019 -
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
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I've just answered this somewhere else. Try the settings below. 25C/40 60C/50 65C/80 70C/100 What this does is that, at lower temps, the fans will not ramp up as fast or as intensely, and it will only ramp up upon actual use. There's probably also a ramp up and ramp down speed adjustment. Set it to the highest you can find. Should be 0.7s and 1.0s respectively.
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Yeah, it’s normal for the fan to speed up
PCPartPicker
pcpartpicker.com › forums › topic › 267234-constantly-changing-fan-speed-help
Constantly changing fan speed? Help!!! - PCPartPicker
I think the problem is a combination of the monitoring being extremely sensitive to changes in temps and applying too much or too little voltages / PWM signal to the fan for those moments. Sadly no way to smoothen out or delay fan spin up and down time. This is problematic with CPU's which ...
Videos
Quora
quora.com › My-CPU-fan-seem-to-be-spinning-at-inconsistent-speeds-And-performance-issues-had-started-ever-since-How-do-I-fix-that
My CPU fan seem to be spinning at inconsistent speeds. And performance issues had started ever since. How do I fix that? - Quora
Follow these steps methodically: most inconsistent fan-speed problems are solved by cleaning, reconnecting, matching fan/header type, reseating the cooler, or replacing a failed fan. ... Why is my CPU fan running at max speed? Whenever I played a game, my CPUs fan never went this fast. How do I make it run slower? On my PC ...
Tom's Hardware Forum
forums.tomshardware.com › home › cooling
[SOLVED] - CPU fan is running rather erratically | Tom's Hardware Forum
March 19, 2020 - Why' What you describe sounds something like the mobo has detected a "fan failure" and is trying to ensure it re-starts. I really doubt your fan is failing. BUT on some mobos for each fan header there is a setting you can adjust for what the MINIMUM fan speed should be before the mobo calls that a failure.
Reddit
reddit.com › r/buildapc › inconsistent fan speed
r/buildapc on Reddit: Inconsistent fan speed
March 11, 2021 -
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?
Box
box.co.uk › blog › case-fan-noise-vibration-fix
Case Fan Noise and Vibration: Causes and Fixes
January 7, 2026 - Fluctuating speed is usually caused by sensitive fan curves, control mode mismatch, or power issues from splitters or hubs. Grinding sounds, inconsistent start-up, and noise that does not improve after adjustments are strong signs that a fan ...
H|ard|Forum
hardforum.com › [h]ard|ware › overclocking & cooling
Inconsistent fan speed at idle | [H]ard|Forum
April 13, 2019 - I set the "curve" to be flat vs temp with the fan speed just high enough to do the job. So say 40% @ 20 deg, 40% @ 30 deg, 40% @ 50 deg, 40% @ 70 deg, then let it go on up to 100% at 85 deg.
Reddit
reddit.com › r/pchelp › pc fans run inconsistently
r/pchelp on Reddit: PC Fans Run Inconsistently
April 16, 2024 -
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?
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Are they PWM fans? If they are they might be running on the default fan profile in the bios. They will go a certain percentage depending on your CPU temp. I think Asus uses Armory crate to control RGB and fan speed.
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Tom's Hardware Forum
forums.tomshardware.com › home › components
Fan seems to be inconsistent | Tom's Hardware Forum
September 25, 2013 - My fan is running at 2.3k rpm while my CPU temp is idling at 50-55c. I know its the CPU fan as I turned down the Max speed and it was a lot quieter.
Ars OpenForum
arstechnica.com › forums › hardware & tweaking › case and cooling fetish
CPU fan keeps wavering - what's causing it? | Ars OpenForum
June 18, 2012 - I had the same problem with my ... quick (41c), slow the fan down, warm up (45c), rinse, repeat. You can try setting the goal temp in the BIOS either higher (thus running slower more often) or lower (running at a higher speed because it just can't Quite reach goal ...
Reddit
reddit.com › r › pcmasterrace › comments › 1o09yuq › laptop_pc_fan_speed_inconsistent
PC top panel's fan's speed is slowing down and speeding up ...
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HP Support Community
h30434.www3.hp.com › t5 › Notebook-Software-and-How-To-Questions › Problem-With-Randomly-Fluctuating-Fan-Speed › td-p › 7595310
Problem With Randomly Fluctuating Fan Speed - HP Support Community - 7595310
May 15, 2020 - I got a couple apps to monitor fan speed and cpu temperature. The temp changes slowly between 60 and 70 and from what i know thats pretty normal. The fan speed however will go from 0 to 3000 to 6000 RPM back and forth every couple seconds. Sometimes it will stay on 6000 RPM for like 30 minutes even when the temperature is low 60s.
Corsair Community
forum.corsair.com › forums › legacy topics › corsair product discussion › cooling
Constant up and down fan speeds with no load - Cooling - Corsair Community
November 20, 2019 - I have Corsair H100i V2 It keeps cpu nice and cool but once windows 10 loads, the chassis fans rev up and slow down almost in a pulsing way. I don't even have to be doing anything on the PC I can be reading a book, but as long as windows is loaded it does it. And when I just move the mouse a litt...
Cybersided
cybersided.com › home › random pc fan revving: what causes it & how to fix it
Random PC Fan Revving: What Causes It & How to Fix It
September 17, 2021 - The fan curve is basically the control profile of your fan controller. It specifies how fast your fan should spin depending on what the CPU temperature is. For instance, your fan curve might specify 30% speed at a temperature of 25C, 40% speed at a temperature of 30C, and so on.
Steam Community
steamcommunity.com › discussions › forum › 1 › 1643170903506592365
Pc fan goes crazy :: Help and Tips
August 13, 2019 - Originally posted by Fopans ... why fan speed can be high is that the thermal paste that transfers the heat from the processor to the processor fan has hardened and dried out....
PCMAG
pcmag.com › home › how-to › components
Noisy Computer Fan? Try These 6 Fixes Before Calling Tech Support | PCMag
October 7, 2025 - Play around with the fan controls and see what works. Some will only offer basic "high" and "low" fan settings, while others may provide advanced fan curves that let you set the fan speed at different CPU temperatures. Certain motherboards can control all connected fans, while others may only control fans with 4-pin PWM adapters (rather than cheaper 3-pin models).
Tom's Hardware Forum
forums.tomshardware.com › home › components
CPU fan speeds up for no reason, then slows down again | Tom's Hardware Forum
November 23, 2017 - The thermistor could be bad but that would be very rare in my experience. I would look at what processes are running when the CPU starts spinning up. As always check for a BIOS update and besure you have an adequate CPU fan as well as adequate fans for the case.
HP Support Community
h30434.www3.hp.com › t5 › Gaming-Notebooks › Erratic-Fan-Speed › td-p › 8322775
Solved: Erratic Fan Speed - HP Support Community - 8322775
March 19, 2022 - And, also clean the air vents to reduce fan workload. Turn off the computer. Remove any objects near the computer. Use a vacuum to remove the dust from the vents underneath and on the sides of the computer. Turn the computer on, and then place it on a hard, level surface, such as a desk or table. Refer to the article: HP Notebook PCs - Fan is noisy and spins constantly (Windows) By the end of the article you will be able to isolate the issue.
HP Support Community
h30434.www3.hp.com › t5 › Notebook-Hardware-and-Upgrade-Questions › My-Laptop-Fan-Speed-is-Slow-and-Constant › td-p › 7651246
My Laptop Fan Speed is Slow and Constant - HP Support Community - 7651246
June 23, 2020 - I understand that Laptop Fan Speed is Slow and Constant. I would like to inform you that the fan functions are system managed and there is no HP tools or options to turn on or off the system fan manually. I'm afraid that's how the HP device is designed, making changes to fan speed may cause overclocking or over-throttling causing hardware malfunctions within the device and hence is not recommended or supported by HP.