How many PWM fans can a motherboard take? Fan header splitting

[nutzaalex]

I've built a few systems in my life, sometimes I split a motherboard fan header to be able to use multiple fans.

 

Recently, I upgraded a system, a msi B450 mortar max to which I hooked up 6 fans to its 3 fan headers, 2 for each:

2x noctua nf-a14

2x noctua nf-f12

2x factal design silent series 120mm

got a noctua nh-d14 cooler so even the CPU fan header is spit in 2

 

So I started asking myself, how many fans is too much? Can the motherboard take so many fan headers split?

[Levent]

It depends on the fan and the rating of your fan headers. Which might be defined in user manual.

 

 

IIRC my Asrock board claims 1amp per header is their absolute limit. So that means I can run 3x300mA fans per header.

 

2 is usually a safe bet.

[nutzaalex]

5 minutes ago, Levent said:

It depends on the fan and the rating of your fan headers. Which might be defined in user manual.

 

 

IIRC my Asrock board claims 1amp per header is their absolute limit. So that means I can run 3x300mA fans per header.

 

2 is usually a safe bet.

I've read that usually it's 1amp per header, sadly my manual or the MSI website does not provide a value.

 

Looking on Noctua's page for one of my fans it's says input current typical 0,03A max input current 0,05A, which would translate to 50mA, so technically I could run way more (not that I will), but are their fans very efficient or is my math wrong? 

[Levent]

2 minutes ago, nutzaalex said:

I've read that usually it's 1amp per header, sadly my manual or the MSI website does not provide a value.

 

Looking on Noctua's page for one of my fans it's says input current typical 0,03A max input current 0,05A, which would translate to 50mA, so technically I could run way more (not that I will), but are their fans very efficient or is my math wrong? 

NF-A14 > 0.13amps

NF-A12 > 0.14amps

 

I am not sure what you looked at.

[Godlygamer23]

3 minutes ago, nutzaalex said:

I've read that usually it's 1amp per header, sadly my manual or the MSI website does not provide a value.

 

Looking on Noctua's page for one of my fans it's says input current typical 0,03A max input current 0,05A, which would translate to 50mA, so technically I could run way more (not that I will), but are their fans very efficient or is my math wrong? 

Considering that Noctua advertises a wattage value of 0.6W(12V*0.05A) on the spec sheet, I would believe that to be a correct value.

[Godlygamer23]

2 minutes ago, Levent said:

NF-A14 > 0.13amps

NF-A12 > 0.14amps

 

I am not sure what you looked at.

https://noctua.at/en/products/fan/nf-f12-pwm/specification

 

It states a max amperage value of 0.05.

[Levent]

Just now, Godlygamer23 said:

https://noctua.at/en/products/fan/nf-f12-pwm/specification

 

It states an amperage value of 0.05.

Oh F fans, yeah non static pressure optimized fans should pull less amps.

[Godlygamer23]

12 minutes ago, Levent said:

Oh F fans, yeah non static pressure optimized fans should pull less amps.

Seems like they're static pressure optimized as well though.

[nutzaalex]

regardless of the exact value, if a header can do 1 amp max, it seems one can split a header quite a few times before it becomes a problem  since most motherboards come with more than 1 header, why do fan splitters from sata exist?

[thrasher_565]

back in the day people said about 10 pwm fans but i dont no. there ways of boosting it. but with so many fan headers on mb these days. it posable that hubs bost it so each 10 fan hubs so 10x 10 per header...

 

unless you build a pc like me your probably fine...

Edited May 21, 2024 by thrasher_565

[thrasher_565]

5 hours ago, nutzaalex said:

regardless of the exact value, if a header can do 1 amp max, it seems one can split a header quite a few times before it becomes a problem  since most motherboards come with more than 1 header, why do fan splitters from sata exist?

the sata is for the power of the fan. the pwm is different. and the tac is also different.

the ground and voltage 12v mostly (can be 5v too) well the pwm tells the fan to turn on/off and how long. the tac tells the pc what speed its ruining. vs dc fan were the controller reduce or increase the voltage. why this is bad is because constend changing was hard on the controllers in theory but fans used more power then they do now. 48v would be ever better but pcs dont do 48v for w/e reason and yes there were 48v server fans but my guess was power elsewhere

 

3 fase motors. were it starts at like 12v then 24v then 48v the 12v has the amount of amps to get it spining well once spining need less power to keep it spining so it witches to 48v. same thing as adding a fly wheel the mas of it stores emery helps to smoothing things out. or as far as i under stand it anyway.

 

its posable that the heat the controllers on the mb were cussing problems with ocing but i dont no i heard wired things about ocing

Edited May 21, 2024 by thrasher_565

[TPCEA]

12 hours ago, nutzaalex said:

regardless of the exact value, if a header can do 1 amp max, it seems one can split a header quite a few times before it becomes a problem  since most motherboards come with more than 1 header, why do fan splitters from sata exist?

Be careful. Take the Noctua NF-A14 iPPC-3000, which pulls about .65A, and then you start to see the potential for problems. Just make sure what the max amperage is for each fan and that you don't go over the header limit unless you have a hub or controller. 

 

15 hours ago, nutzaalex said:

since most motherboards come with more than 1 header, why do fan splitters from sata exist?

Some people just want to have a powerful fan running, but they use more than 1A, so a hub or controller with a cable to the PSU resolves that issue .