MSI motherboards fan headers

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glytch5

glytch5

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So I have ran into the age old problem... using fan splitters from single motherboard headers.

Most of my headers are using a dual fan splitter... and I am needing to do a 3 fan splitter... I understand the whole idea that most of the time headers are about 1amp... so do your wats over voltage to figure out the fans amperage, and add it up...

However I called MSI to talk with them about this, and they guy flat out told me like 3 times to NEVER put more than one fan on one of their headers... he said the wires bringing the power to the headers are very thin, and the solder joints will easily melt...

I have 3 noctua NF A14 PWM fans... they each are about .13 amps... you would think 3 of those would be no problem on one header, but the guy kinda worried me... so these fans are (1.56w/12v=.13A) correct? so .13A X 3 fans = around .4amps.... which would leave plenty of room...

What do I do?
 
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Nihilanth


Thing is just because its a 4 pin header doesn't mean it has PWM control. Like most CPU fan headers, yours most probably has PWM control but many boards have sys/chassis 4 pin fan headers that don't actually do PWM. As in there's no PWM signal on the...
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Nihilanth

Nihilanth

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Jun 13, 2011
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Being a MSI rep, he was never going to say its fine, no problem, go ahead with it. He was always going to dissuade you from doing anything that would even remotely harm one of their products. A rep on the MSI forums told me not to increase power limit at all so the response you got was to be expected.

1 amp is normally what it is but sometimes it can vary. Best thing to do is find out just how much current your fan headers can draw. Check the manual or ask someone with the same board. Btw, which board do you have?

Your math is correct but the thing you should know is that fans pull more than their rated current for a second or two when they are started. Your three Noctua fans will pull more than 0.39amps when you first boot up your PC. Doesn't hurt to leave some room to accommodate for this surge. In your case, you should be fine even if your fans pull twice the amount of current but its something to consider when adding more than 2 fans to one header.

As for that splitter you've linked to, it depends on your fans. Are your fans 3 pins or 4 pins? If I am not wrong, you can only control the speed of PWM fans with that kind of PSU powered splitter and only when connected to a fan header which can do PWM. If you plan on buying that, you need to find out whether the fan header you intend to plug it into is capable of PWM.
Read Paperdoc's posts in this thread for more info: http://www.tomshardware.com/answers/id-3256445/wpm-splitter-work-pin-fans.html
Also, this might be a better alternative: https://www.amazon.com/Swiftech-8W-PWM-SPL-ST-Way-PWM-Splitter-Sata/dp/B00IF6R4C8/ref=sr_1_1?ie=UTF8&qid=1512631405&sr=8-1&keywords=swiftech

Now, if all you want to do is run three fans from a single fan header that at least has voltage control, then something like this would be enough: https://www.amazon.com/Silverstone-Technology-Sleeved-Splitter-CPF02/dp/B00HJOJS9O/ref=sr_1_6?ie=UTF8&qid=1512629971&sr=8-6&keywords=fan+splitter
Basically, a couple of fan splitters daisy chained together. If you got a couple lying around, you could do it yourself.

 
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glytch5

glytch5

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Unfortunately my motherboard manual has zero information about the subject, that was my first attempt.

The board is an MSI pro carbon X370. All of the fan headers are indeed 4 pin PWM. So I was thinking with that aux power splitter I linked, I would get the voltage reading somewhat accurate, so long as the fans were all the same... and all PWM.

I had my eye on that swiftech thing, but the problem is the fan headers on the unit are on top, not on the side making it a mega pain.
 
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Nihilanth

Nihilanth

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Jun 13, 2011
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Thing is just because its a 4 pin header doesn't mean it has PWM control. Like most CPU fan headers, yours most probably has PWM control but many boards have sys/chassis 4 pin fan headers that don't actually do PWM. As in there's no PWM signal on the 4th pin, its just like a 3 pin fan header only with an extra pin so fan speed can only be controlled via voltage change.
http://noctua.at/en/how-can-i-check-if-my-4-pin-fan-header-supports-pwm?___from_store=es

So if you purchase that fan splitter you linked to and the header you plug it into isn't a true PWM pin, your fans will run full speed no matter what. This is because with that splitter, the power to your fans is being supplied by the PSU and not the fan header. So if there's no PWM signal to control the voltage supplied by the PSU, you can't control the speed of the fans. Also, you can't control the speed of 3 pin fans with that kind of splitter period.

The reason I suggested the Silverstone splitter as an alternative is because its a straightforward fan splitter with no external power source so it doesn't matter if your fan header has PWM control or not. As long as there's at least voltage control (which your fan header should most definitely have) and you stay under the rated current draw, you can control the speed of 3 pin as well as 4 pin fans (unless you mix and match them). Hope that helps.

 
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