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Build issue - conntecting case fans to psu/mobo

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November 2, 2007 2:39:31 AM

Components:
PSU: Corsair HX 620
MoBo: GA-P35_DS3R
Chassis: Antec 900
GPU: 8800GTX

Hi all. I have some build questions about connecting the chassis fans to power , and also my 8800gtx to whatever power source I need to connect it to.

I have 4 fans on the 900 that I need connected, however my MoBo's 4pin connector is already being used by the CPU cooler and only has two more, 3 pin connectors - my fans have 4 pin connectors, and I think 4 pin molex connectors.. What I have done is connected the bigger 4 pin (molex?) from the fan, to a cable that runs to my PSU. What I want to know is why I can connect multiple components on the PSU's molex cable, it has a male/female connector on one piece that allows me to piggy back components...does this mean I can piggy back two of my fans onto 1 molex into my PSU? Does each rail supply enough power for that? I don't think I have enough connectors to my PSU otherwise (e.g. 4 fans, HD, GPU, DVD)., and I don't have a manual that details the power that runs through the rails.

If anyone can shed some light on this for me, and what kind of connectors I need to keep my eye out for to connect my GPU to the PSU I would really appreciate it because I want to finish up my first build - and I want to do it right! :) 

Thanks everyone!
November 2, 2007 3:37:05 AM

Do you have a single or dual 6 pin power connector on the edge of the card?
November 2, 2007 12:17:02 PM

I have dual 6 pin power connector on the gpu. My PSU has two 6 pin power 'holes' off to the side that I can connect them to, I think.
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November 2, 2007 12:40:48 PM

I would dedicate a +12v rail (molex with a 6-pin connector or 2) to the video card. The video card is the most power hungry. You can chain up the fans with 1 power cable/connector.

Don't use the cpu fan connector for a case fan cuz in the event your cpu fan fails, you will have no way to tell, other than an overheating cpu. If you want to take the risk, go ahead & mix 'em up.
a c 90 B Homebuilt system
November 2, 2007 1:22:37 PM

Your 620HX cables:

Do not daisy chain other components off the CPU power supply.
Manual that details the power that runs through each rail (and also talk about connecting fans)
http://www.corsairmicro.com/_productmanuals/Corsair_PSU_English_Manual.pdf

GPU to PSU use PCIe 6 pin connectors.
It wont hurt to run just 2 fans while you are on the lookout for an extra fan power connector cable.
Check the Antec 900 website for accessory products or any of the usual e-tailer outlets.
November 2, 2007 3:38:25 PM

Thanks akhilles/wr2

So as I understand it, I can daisy chain the 4 fans off one 4 pin molex rail from the PSU (is there a way to know what voltage is from this rail?), and let the CPU fan use the CPU fan connector.

Other components, such as HDD and DVD should have their own separate connection to the PSU.

GPU should be connected with the two 6pin +12v molex connectors.

Also, if the four fans run at about 3A each, does that mean I have 12v and 12A coming through the rail since they are daisy chained?

Lastly, I have 5 4pin connectors off the PSU, and 2 PCI-E connectors...does the PSU automatically know to send out the proper voltage? Ie +12v, +5VSB, +5V, +3.3V? Are all 5 4pin connectors 12volts?

If anyone knows of a PSU for n00bs guide, and some intro to electric circuits I would love to read those.

November 2, 2007 4:41:10 PM

I think that you missed a decimal point. 12V fans will not draw 3A
(36W) more like .3A
a c 90 B Homebuilt system
November 3, 2007 3:36:54 PM

Mr Cipher said:
does the PSU automatically know to send out the proper voltage? Ie +12v, +5VSB, +5V, +3.3V? Are all 5 4pin connectors 12volts?
The PSU has single voltage output over multiple rails. +3.3V is just 3.3V, +5V is just 5V, etc.
Any connector will have the voltage of the rail it is plugged or patched into.
The 24pin motherboard connector pinout is shown Here.

!