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Not enough pwr sockets for 7 fans

Last response: in Components
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March 30, 2010 3:02:22 AM

I am putting together a PC and have an 1000w Antec pwr supply.

There are not enough connectors on the motherboard to power the 7 fans (including two for the CPU).

My question is: What is the accepted way to power these additional fans? E.g, Split a pwr socket on the M/B too two sockets? Split a pwr Cable into several sockets? And if yes, can you suggest a supplier.

I assumed that when you got a higher watt power supply this would mean extra power cables for use. But this does not appear to be the case. The 850w has the same number as the 1000w.

System details.
-Asus supercomputer m/b
-Megahalems CPU cooler
-Antec 1000 watt power supply.

More about : pwr sockets fans

March 30, 2010 3:18:42 AM

Thanks shovenose, What about for a 4 pin? Its two fans for the CPU.
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a c 248 ) Power supply
March 30, 2010 3:22:30 AM

Do not split a power socket on the motherboard. The System BIOS monitors fans connected to the motherboard. Trying to run two fans on one socket can cause problems. In addition, the motherboard fan connections may not be able to supply enough power to run multiple fans connected to a single connection. You must connect a cpu heatsink fan to the cpu_fan connection on the motherboard or your system will not work. Connect the second cpu heatsink fan to another fan connection on the motherboard.


You can daisy chain the remaining fans and connect them to one power supply cable. Here is a link to a handy adapter that can be used to connect up to four fans to a single power supply connection:

http://www.frozencpu.com/products/8780/cab-163/FrozenCP...

Depending on the location of the case fans, you might also need extension cables like this one:

http://www.frozencpu.com/products/1091/cab-07/12_3_Pin_...

Those are for typical case fans with 3 pin connections. What kind of power connectors do your case fans have?
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a b ) Power supply
March 30, 2010 3:24:49 AM

sorry. what do you mean? that u have two 4pin fans that you want to connect to the cpu fan port on the mobo? i think the thing i linked to should do that too. please correct me if im not quite understanding the question...
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March 30, 2010 3:34:31 AM

Thanks johnnylucky, the pictures told a thousand words.

shovenose, Sorry, more info. I have two 4pin pwm fans that are for the CPU. I have a CPU cooler that can accept two fans. I would like to use the CPU fan socket for both so I can allow the M/B to control the speed properly. If I connect to the power cable I will lose M/B fan speed control.
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a b ) Power supply
March 30, 2010 3:38:32 AM

do some splicing action. the problem with that is that if u have two fans reporting speeds and stuff to the mobo on the same socket, it will be confused. also, im not sure how much power the mobo cpu fan socket can provide, as its only meant for one fna...
i suggest you just run one of the fans to another connector on the mobo, turn off motherboard fan control, and just use SPEEDFAn or something similar to control the speeds. it might be annyoing though :( 
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a c 248 ) Power supply
March 30, 2010 3:44:31 AM

shovenose - Probably. My ASUS Sabertooth 55i motherboard has two 4 pin fan connectors next to each other near the bottom rear of the cpu socket. One is labelled cpu_fan and one is labelled chassis_fan1. The two 4 pin connectors work with either a 3 pin or 4 pin fan cable.
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a c 248 ) Power supply
March 30, 2010 3:49:44 AM

geoff - You can connect the second cpu heatsink fan to a second connection on the motherboard. In all probability your motherboard will be able to monitor and control both heatsink fans. Check you motherboard manual and go into BIOS at start-up to find out which fans are monitored and temperature controlled. You may have to enable some sort of power management setting.
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March 30, 2010 4:12:31 AM

Thanks shovenose and johnnylucky.

johnnylucky, the problem with using a M/B socket for 1 CPU fan (assuming it is temp controlled) is that it won't alter speed based on the CPU temp. This would lead to a big issue of one of the fans on the CPU cooler in the push pull configuration going faster or slower that the other. But I have enough info now to make a suitable cable.

The solution that will solve the speed reporting that shovenose mentions is:
Make a cable that uses the M/B socket pwr for one fan and for the second fan a power cable. The speed pin will be directed from one fan only. This will give an indicator as to what both are doing speed wise. And the pwm signal will be split between the two fans to allow full control by the M/B. And since they are sourced from the same pwm signal they should be doing the same speed. I just need to draw it up and make it.

Thanks to all for your help.
geoff
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a b ) Power supply
March 30, 2010 1:57:46 PM

sounds good...
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March 30, 2010 9:52:08 PM

Best answer selected by geoff.
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a b ) Power supply
March 30, 2010 10:50:00 PM

Use this http://www.akasa.com.tw/update.php?tpl=product/product.... to drive your two PWM CPU fans.

Whack the fans (up to 4 PWM fans) into this puppy, hook up a molex to actually power the fans, then put the single PWM connector into the CPU fan header. You'll still get the PWM signal going into all fans connected, but the power comes from the PSU itself so the motherboard header isn't overloaded.
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