Question 3pin fans problem

[aedskfnp3]

Hello guys, have a corsair 460X rgb case with 3 SP120 fans 3pin type. Ive heard that they are a bit noisy, but they are a lot more than i could expect. Also i have watercool corsair h100i v2 and i had to place radiator at the front, so 2 of SP fans are intake through radiator atm. I know it would be better to swap them to any other 4pin, but for now cant do more.
So, 2 of these fans are connect to pump and somehow they can work quieter than 3rd one, which causing high temperatures btw. I tried to do same thing with 3rd fan that connected to the motherboard, but in bios i cant set any of max/min fan duty below 60.
So my question is - how does 3pin fans work? It should be running at 1400rpm and no less, but it is 1100/1200 rpm, and my pump somehow can even slow down them
Anyway, if ill buy 4pin fans for radiator, i dont want sys fans to be so noisy. Is there any way to slow down them?

 

[Lutfij]

You might want to look into investing PWM fans for all possible fan mounting locations, including your AIO. You can then have them all connected to a PWM splitter like this and then have that run off a PWM header off the board, while the speed of the fans are tethered to the temps of your CPU, provided your board has that functionality in BIOS or in software.

Speaking of which, please list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

 

[aedskfnp3]

You might want to look into investing PWM fans for all possible fan mounting locations, including your AIO. You can then have them all connected to a PWM splitter like this and then have that run off a PWM header off the board, while the speed of the fans are tethered to the temps of your CPU, provided your board has that functionality in BIOS or in software.

Speaking of which, please list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:

Yea i wont repeat my mistake bying 3pin fans. But i already have them and must mount them in my case. Your advice can work, thanks, but im going to buy corsair commander hub, and sometimes cpu fans have unstable speed, like a wave, that can cause noise, but if there is no other way ill have to do like you said
My pc:

CPU: 8700k
Motherboard: ASUS Z370-f
Ram: 16gb ddr4
SSD/HDD: m.2 mp500 240gb/seagate barracuda 1tb
GPU: gtx 1070
PSU: i dont actually know model, some 750W 80plus certification
Chassis: corsair 460x RGB
OS: Win10 1803

 

[aedskfnp3]

I just cant understand why corsair making uncontrol fans with so high speed, they are not even close to silent, at least, my understanding of silent.
Really, 800-900rpm would be enough. They cost so much, and they works so bad.

 

[Karadjgne]

Analog (3pin) fans work on voltage. It takes a certain amount of voltage to kick the fans started. In good fans, this is 5v (40%) but for many fans it's 7v (60%). They'll only run 5v-12v. Bios doesn't care about rpm as such. It operates on duty cycles. Default duty cycle is 60%-100% for analog fans. Since those fans max out at 2350rpm, and operate 7v-12v, that's 100%, and 60% would be be 1400rpm. If the pump is allowing the fans to run at a lower voltage after a 7v start voltage, that'll be the software/pump choice and 1100/1200rpm, but the fans will not spin any slower as they'll need a certain amount of voltage to operate.

PWM fans are a constant 12v and the pwm pulse triggers an on/off state. Because they are still 12v, they can go much lower in duty cycle, as low as 20% on average.

 

[aedskfnp3]

Analog (3pin) fans work on voltage. It takes a certain amount of voltage to kick the fans started. In good fans, this is 5v (40%) but for many fans it's 7v (60%). They'll only run 5v-12v. Bios doesn't care about rpm as such. It operates on duty cycles. Default duty cycle is 60%-100% for analog fans. Since those fans max out at 2350rpm, and operate 7v-12v, that's 100%, and 60% would be be 1400rpm. If the pump is allowing the fans to run at a lower voltage after a 7v start voltage, that'll be the software/pump choice and 1100/1200rpm, but the fans will not spin any slower as they'll need a certain amount of voltage to operate.

PWM fans are a constant 12v and the pwm pulse triggers an on/off state. Because they are still 12v, they can go much lower in duty cycle, as low as 20% on average.

Thank you for your answer! Maybe there is any adapter that force fan to take more voltage?
My bios has option auto-config fans or something. So, during this process fans starts to spin at highest speed, at near the end it was really quiet. When process was ended, they started to spin as always - loud. Idk how, but thats what i heard myself

 

[Karadjgne]

Sorry, no adapter. The fan motor itself is only rated for 7v-12v, any more than that and it'll burn out. Realistically more voltage will mean higher rpm ans more noise.

The only cure for corsair SP120's lies in the bottom of a trash can. I'd suggest Noctua NF-F12 pwm, Scythe GT's, Corsair ML120 or any other decent fan (nzxt/fractal design/Phanteks M) that gets decent sp/cfm at lower rpm.

Any 1000rpm 3pin will spin at 600rpm at 60%, a pwm will be closer to 400rpm (1200rpm)

 

[aedskfnp3]

Sorry, no adapter. The fan motor itself is only rated for 7v-12v, any more than that and it'll burn out. Realistically more voltage will mean higher rpm ans more noise.

The only cure for corsair SP120's lies in the bottom of a trash can. I'd suggest Noctua NF-F12 pwm, Scythe GT's, Corsair ML120 or any other decent fan (nzxt/fractal design/Phanteks M) that gets decent sp/cfm at lower rpm.

Any 1000rpm 3pin will spin at 600rpm at 60%, a pwm will be closer to 400rpm (1200rpm)

Do you think corsair ml is better than LL? I saw LL's pack cheaper than ML, with a bit higher air flow. I mean, do ML technology worth it when it comes to perfomance/silent compare to
LL? Lighting dont matter, ml is pretty good for me

 

[Karadjgne]

The ML are almost silent. Equitable to Noctuas. Have to understand you can't always go by the max results. Ppl rarely spin fans at 100%. So you'll want fans that work well at less than 100%.

 

[aedskfnp3]

The ML are almost silent. Equitable to Noctuas. Have to understand you can't always go by the max results. Ppl rarely spin fans at 100%. So you'll want fans that work well at less than 100%.

Thank you