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Case fans - how to connect?

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September 16, 2011 7:23:11 PM

Hello,

Recently I've bought components for a new pc. The case an Antec Nine Hundred Two. There are 4 big fans with it. All those fans have 1 big 4 pin connector (I think they're called molex or something). So my problem is, I don't exactly know how to install it. What I did now is connect all those 4 molex connectors to eachother, so you have on big thing, and the put that in such a same molex connector in the PSU. Did I install this in the right way? The system fan on my old pc went directly into the motherboard, but not into the PSU. So am I doing it right?

Thanks in advance,

Arjen Vandervelde

More about : case fans connect

a b ) Power supply
September 16, 2011 7:28:31 PM

Yes, now they're just all running at ~100%. However, if it isn't a problem for you (noise-wise), then it's all good.
September 16, 2011 9:22:25 PM

arjenboerdijk said:

What I did now is connect all those 4 molex connectors to eachother, so you have on big thing, and the put that in such a same molex connector in the PSU. Arjen Vandervelde



Just a note...a friend of mine had a case (the name and type slips my mind) in which he had about 8 or 9 fans chainlinked together then attached to one molex from the PSU. That HUGE ELECTRICAL DRAW of all those fans were causing him start-up issues with his video card....I wouldn't recommend any more than 4 fans chain linked together on any ONE molex connector....if you do decide to add more eventually...
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a b ) Power supply
September 16, 2011 11:09:23 PM

if its too loud just get molex to 3 pin (or 4 pin) if your board has them adaptors and plug them in the motherboard headers

a b ) Power supply
September 16, 2011 11:39:51 PM

What i would do is plug em into different molex connectors from your PSU and not daisy chain it all into one. From what I understand, it can cause a lot of problems for you and is not recommended by many to do so.
a b ) Power supply
September 17, 2011 4:10:48 AM

I think lilotimz is too cautious - Molex connectors can supply many amps, and a fan is typically less than half an amp at max - startup time - and much less when running. Four on one Molex seems OK to me.

Do your Antec fans also have small leads coming out of them with a little 3-position switch on the end? If so, those are Antec Tri-Cool fans. The little switch allows you to set the fan speed manually as you wish, according to your cooling needs.
September 17, 2011 4:27:13 AM

If you have a multi rail psu you should be good to run them on the same line if not see if you have a single rail psu. If so It could affect your gpu power and may loose out some. whats your comp specs and what psu do you have.
September 17, 2011 4:55:44 AM

briansklein said:
If you have a multi rail psu you should be good to run them on the same line if not see if you have a single rail psu.



I would almost think a single rail PSU would be the better bet for heavy loading on one line seeing as all wires come from the same rail. With a multi rail, they are fed by seperate rectifiers/regulators; you could have your CPU, GPU or many HD's on the same rail that has the heavy loading from too many fans. As far as I know multi-rail PSU's don't like cross loading between rails too much...I still think the best bet is limit the fans on any one molex to less than 4. as mentioned before, start up current in fans is usually more than it's amp/watt rating on it's sticker.
September 17, 2011 10:11:50 AM

briansklein said:
If you have a multi rail psu you should be good to run them on the same line if not see if you have a single rail psu. If so It could affect your gpu power and may loose out some. whats your comp specs and what psu do you have.


My pc specs are;

MSI P55-GD85 Mobo
Intel Core i7 OC @ 4.0 GHz
Scythe Mugen 2 REV B CPU Cooler
nVidia GTX320 1024MB
6GB DDR 1333MHz RAM
1TB HDD
PSU max wattage 450W
PSU peak wattage 500W
In my old case this al ran perfectly fine

But now with my new case with 4 big fans instead of one, and all connected together, I don't know...
I don't see where to connect it into my motherboard? I don't have such big connectors on there.

By the way, there's only 1 molex connector coming out of the PSU, on the same cable there's another small 4 pin (in line) connector. I don't know whether to use that one or not.

Will this run fine with my PSU?
a b ) Power supply
September 18, 2011 1:50:43 PM

Using an adapter you could power ONE fan from a mobo fan pinout, the one labelled SYS_FAN. If your mobo has two of these, then you could do that twice. You even could do some wire splicing and power two fans off each mobo SYS_FAN pinout. Those mobo outputs usually have some fan speed control in them, so you could get your fans to run more slowly and quieter that way if you want to. BUT if you do, let us know. There's a small point about splicing fan wires together.

But I suspect you would rather not do that, and just keep what you have. Apparently your PSU is a newer one that expects you to have very few devices that use Molex 4-pin power inputs - these are typically IDE HDD's and old 5¼" floppies, but also include IDE-connected optical drives. Putting 4 fans on the one Molex output should be OK. IF you need to, you can get a Molex splitter that makes two outputs from one. By the way, the smaller connector on that same PSU output line is VERY likely for a 3½" floppy drive you don't have.
September 18, 2011 4:32:37 PM

Ok thanks a lot for all of this useful information! I hope it's gonna be ok. I'll test my pc monday, because then I'll receive an extra 4 pin cable for CPU power, cuz my current one is too short. I'll report back right then.

Thanks a lot.
!