# Stacking fan power cables



## Nevermore0 (Aug 5, 2010)

I built my own PC but I'm far from an expert at it. My motherboard is an MSI Z87-G43, which has 2 CPU fan and 3 system fan slots. My case has 5 fans - 2 on the front, one on top, one on the back, and one on the side. I've been plugging my fans directly in to my PSU, but I'm sick of them running at full blast all the time. I was wondering if I can plug 2 or 3 of them together and then in to the mobo.

One problem I face is that 4 of the fans use large 4-hole plugs, and the jacks on the mobo are small. I would need some kind of converter. The rear fan is plugged in to the mobo already, as it uses a smaller plug. And the third system fan port is hidden behind my graphics card, so I'm not sure it's usable - it might be, if I can convert the big plugs to little ones. I would need to know what that cable is called if I'm going to search for it to buy it.

If the third system fan jack is unreachable, would it be a problem to plug them in to my unused CPU fan jack? I know there'd be a temperature difference, but my BIOS has separate options for each fan, so I could set that fan up independently.

Thanks for your help.


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## VividProfessional (Apr 29, 2009)

https://www.amazon.co.uk/3pin-power-4pin-molex-adapter/dp/B000H25PBK 

one of these might do?

depends on what Voltage the fans are? are they 5v or 12v?


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## Bill_Bright (Dec 17, 2004)

> I was wondering if I can plug 2 or 3 of them together and then in to the mobo.


Not a good idea. Motherboard fan circuits are designed to handle the current requirements of 1 fan per connector only. Plus motherboard fan connectors are monitored by the BIOS and load and speed information might seem erratic causing faults.

Do you really need that many fans? 5 case fans is a lot. Most computer cases can provide enough air flow with just 2 fans, preferably 1 in front pulling cool air in and 1 in back exhausting heated air out. And the PSU fan typically helps too if top mounted. 

What are your temps?

Reducing the fan speeds will reduce their air flow - which might increase heat build up. But reducing the number of fans will do the same thing so I would try just two fans, maybe a 3rd on top. And the largest fans your case support. Big fans move lots more air, but at a lower RPM, thus creating less noise. 

If you really need the extra cooling 5 fans provide, you should look into a fan speed controller between the power supply and the fans instead of combining fans on a motherboard fan header. 

Also, I have found in some cases, a side panel fan actually hinders cooling rather than help. You want a nice "flow" through the case, typically front-to-back and/or bottom-to-top. It seems a side panel fan can cause too much turbulence and disruption to that desired "flow".

Plus, the side fan is mounted on a large metal or plastic panel. I have found instances where the fan noise is almost amplified by and reverberates through that panel for increased noise. 

So I don't like side panel fans EXCEPT when they fire into a connected tube that channels the air directly onto a CPU or graphics card.


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## Nevermore0 (Aug 5, 2010)

Alright, thanks for the info Bill. I'm really not sure what voltage the fans are, nor do I know how to find out. I'll install some kind of program to give me the internal temperature to check, but I don't think overheating has ever been a problem for me. I should be fine with 3 fans.

Thank you for the link Dave, it helped me figure out what I need, which is a male Molex to female TX4.

There shouldn't be any problem using the spare CPU fan header if I can't reach the third system fan header, should there?


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## Bill_Bright (Dec 17, 2004)

I use and recommend Core Temp to monitor my CPU temps. I like it because it has a system tray applet so you can always keep an eye on your CPU temp. 

HWiNFO64 is a great hardware monitor tool, though the amount of information can be overwhelming at first. But it does not have a real-time system tray applet. 

Computer case fans are almost always 12V.


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## Nevermore0 (Aug 5, 2010)

I don't know why it seems like my setup is so unusual... The 4 fans have Molex plugs, with both male and female ends, so I can use either type of jack to hook up to those. My mobo has 4-pin male connectors for the fans. 90% of the small ends of the adapters I see have male ends, and I can't figure out why. I think this should do the trick, I'm just not totally sure that it will control fan speed:
https://www.amazon.com/kenable-Power-Converter-Adapter-Female/dp/B008LBEM4A/


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## Bill_Bright (Dec 17, 2004)

That is just a connector adapter, it is not a speed controller. If you use that, the fan will receive full voltage, thus run at full speed and noise levels.


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## Nevermore0 (Aug 5, 2010)

Does the motherboard not control the speed, through the voltage? I would have thought that as long as it was going to the MB and not the PSU then the speed should be regulated.


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## Bill_Bright (Dec 17, 2004)

The motherboard will control the CPU fan speed and often the System (chipset) fan (if your board uses one). But typically not the case fans - at least not automatically.


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## Nevermore0 (Aug 5, 2010)

Got it. So the fans that came on my case use Molex connectors, which means their speeds can't be controlled by the motherboard. I get it now. I'll try disconnecting a couple of them to reduce noise, and keep an eye on the temperatures. If that doesn't satisfy me, I'll buy some fan controller hardware.

Thanks for all your help.


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## Bill_Bright (Dec 17, 2004)

> So the fans that came on my case use Molex connectors, which means their speeds can't be controlled by the motherboard.


The type of connector really has nothing to do with it. Those fans have Molex connectors simply because they were intended to be power directly from the PSU. 

And again, case fans (even with the smaller connectors) typically are not "controlled" by the motherboards. They might be monitored (depending on the fan), but not controlled.


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