Case fan hook up confusion

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Seance

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I have a mother board that only has one 4 pin slot for system fans. Both of my case fans are 3 pin hook ups. The psu has molex connectors on it as well as a 4 pin in the same zip tied pre-made wires that the molex connectors are on. Do I need to plug the 4 pin into the mobo and buy the molex adapters? Or should I just buy a 4 pin splitter with 3 pin hook ups and just plug the case fans in this way and don't use anything off of the power supply? Extremely confused and any info would greatly be appreciated. I don't want to fry the mother board if the 4 pin from the psu isn't supposed to be plugged in. Also I'm wondering if there's going to be issues if I split the two fans with a splitter like this..

https://www.newegg.com/Product/Product.aspx?Item=N82E16812162026&ignorebbr=1&nm_mc=KNC-GoogleAdwords-PC&cm_mmc=KNC-GoogleAdwords-PC-_-pla-_-Cables+-+Internal+Power+Cables-_-N82E16812162026&gclid=CjwKEAiArvTFBRCLq5-7-MSJ0jMSJABHBvp0pGWTcoPnmtldNsuFdd4O6R0oTvuzlD9IEgxfDVxcCxoC3hnw_wcB&gclsrc=aw.ds

Please be gentle this is my first build. Thanks in advance.
 
Solution
raisonjohn
Plugging that remaining fan header (4-pin system fan) on your motherboard is OPTIONAL.

Now you have the option of plugging your 2 system fans via 1) that 4-pin motherboard headet, 2) the PSU via molex-to-fan cable, or 3) 1 fan via mobo and 1 fan via PSU.

Plugging a 3-pin fan to a 4-pin mb headet is supported. The effect is the fans (which are DC) would run at full speed (esp. if that 4-pin header is PWM). If the 4-pin header is non-PWM, then the 3-pin fan's speed can be controlled by changing the voltage input.

If you opt to plug the fan via PSU, then it synonymous to the former scenario (will run at full speed witb no control).

Usually, the fan headers are rated at max. 1A. If your fans' total ampere draw is less than that, you can...
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raisonjohn

raisonjohn

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Plugging that remaining fan header (4-pin system fan) on your motherboard is OPTIONAL.

Now you have the option of plugging your 2 system fans via 1) that 4-pin motherboard headet, 2) the PSU via molex-to-fan cable, or 3) 1 fan via mobo and 1 fan via PSU.

Plugging a 3-pin fan to a 4-pin mb headet is supported. The effect is the fans (which are DC) would run at full speed (esp. if that 4-pin header is PWM). If the 4-pin header is non-PWM, then the 3-pin fan's speed can be controlled by changing the voltage input.

If you opt to plug the fan via PSU, then it synonymous to the former scenario (will run at full speed witb no control).

Usually, the fan headers are rated at max. 1A. If your fans' total ampere draw is less than that, you can safely plug in 2 fans off of 1 header via a fan splitter cable.

To eliminate the need for a cable, you can choose option 3). Just plug one 3-pin fan into your 4-pin mb header and plug the othet 3-pin fan via PSU.
 
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Seance

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Both fans are fractal design. One is a 120mm fan the other is a 92mm fan. Both together are coming in under 1A... So would this just be easier to use a splitter for this setup? The mobo is a MSI h110m pro-vd Plus... i'm looking through google but not finding any information on the sys fan header amp rating.

 
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raisonjohn

raisonjohn

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If it's substantially under 1A (I'm guessing around ~0.55A?) you'll be safe to use a splitter.

Fan headers, when not specified in the manual, are generally 1A. Some Asus MB's though features 3A (for higher amp fans). Yours does not but 1 header should handle fans up to 1A.
 
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