Crazy PWM Fan Curve?

I just got the MSI B 450 Tomahawk motherboard. I have a Fractal Define F7 case with 3 x 140mm Noctua AF-14 PWM fans in the front, a Noctua NH-D15 CPU cooler and a Noctua AF-14 ULN exhaust fan.
For some reason the fans are very loud with the default smart fan motherboard configuration so I decided to play a little with that setup since the CPU was already pretty cool and I wanted to decrease noise by a lot. Unfortunately no matter what fan curve I set the RPMs of the fans tend to dance up and down the curve even if the temperature doesn’t change. It’s very annoying because it sounds like a winter storm outside a cabin. Right now the only solution I’ve found to avoid this behavior is to set a flat line setup for all temperatures, but that gets my PC a bit hot and is also a bit impractical - I don’t mind the fans kicking in if the PC is hotter but I don’t get why they dance like that all the time even if they don’t need to. I even installed MSI Dragon Center and I was looking at the fan RPM chart in real time and it was literally doing some chaotic movements up and down. The movements are not completely random they seem to be determined by the fan curve + if I flatten the curve the RPMs become consistent. Any ideas how to get a nicely working fan setup? Thanks.

Ryzen processors are known for spiking when they boost for a brief second so it might look like their temperature is not changing over time but opening a program, a tab in your internet browser or something happening in the background might make it spike so that’s why you might see fans dancing up and down.

My suggestion is to set a flat line up to 60°C. That’s how I’ve setup my Ryzen system and fans are staying quiet during day to day usage and picking up speed only when I’m doing something heavy like gaming.

P.S. if you don’t spike that high you can set the flat line lower, up to 50°C or even 45°C. I don’t think any lower will help since I think that with an NH-D15 you’re running around 35°C true idle temp without spikes.

I second MetalizeYourBrain suggestion, i also seen Ryzen spikes a lot for brief amount of time even on light loads or just idling, so i did something very similar to his suggestion, i setup the rpms of the cpu cooler as high as i could (without me able to listen to them) and set the first breakpoint at 60c, from there a very steep graph till 85c 100%, resulting in a very quiet setup as it masks all the spikes but does react if you load it up. Important part is to stablish your spiking temp and the max rpms you willing to sustain for that temp.

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