system fan question

[markkerr]

I am setting up a new system. The Biostar M7MIA motherboard has two fan
connectors: 1) CPU 2) system Fan. My Enlight 7237 case comes with a front
case fan. I have purchased a fan for the rear of my case. My question is
do I plug the front system fan into the power supply and plug the rear fan
into the motherboard? Can I plug both into the motherboard? The front fan
has a four pin connector. the rear fan has a 3 pin connector. the
motherboard has a 3 pin male connector. I have a 3pin to 4pin adapter for
the rear fan if I want it plugged into the power supply.

Thanks for your help

[Cricket]

Hi markkerr,

Yes, you can connect either front or rear fan into the motherboard case fan header. You could also use the adapter so that both 3 pin and 4 pin fans are connected directly to the power supply. Personally, I connect all case fans to the power supply instead of the motherboard fan headers.

The motherboard fan headers do allow you to monitor case fan RPM via the BIOS or Windows software System Health Monitors. If you're overclocking the CPU, these may be important to keep track of...but if you are running the CPU at stock speeds, you really don't need to be monitoring the fans.

Cricket

[markkerr]

Thanks, sounds like good advice!!
I will plug both fans into the power supply
since I have plenty of four pin connectors

Mark

[q2418130103p]

I know this is alittle of the subject, but its not really worthy of a new thread.

Do any of you guys know where I can get a Molex to 3 pin adapter?

[Cricket]

I usually check out the local electronics shops for small connectors and things. Radio Shack might have them too.

But here's a on-line vendor that carries them: http://2cooltek.safeshopper.com/58/cat58.htm?692

Cricket

[q2418130103p]

Ok thanx, that just what I need.
But that website led me to another question, how much output voltage does a 3 pin put out. Cause they have an adapter there that lets ou use the 4 pin for power but the 3 ping for the connection. I have a couple 12 v fans, is there enough power on a 3 pin?

[Cricket]

Hi Jamiejc87,

All the fan headers on the motherboard are 12v, it depends on the amperage that the fan draws. You may have to check with the motherboard specs to see how much load you can put on each header. There are some newer high speed fans that do draw quite a bit. For these, some manufacturers will provide a regular 4 pin molex connector to get power directly from the power supply, but provide a 3 pin connector just for RPM monitoring (and in some cases, so the motherboard will power up. Some motherboards don't power up if there is no fan connected to the CPU fan header).

2CoolTek has an adapter if your fan draws too much current to use the motherboard CPU fan header and you have to connect to the power supply leads instead (but still want RPM monitoring capability): http://2cooltek.safeshopper.com/58/300.htm?692

Cricket

[q2418130103p]

Ok I see. Thank you.

But I have two more questions ( I like asking questions )

Will a fan that uses molex that you attach a 3 pin adapter to be able to have its RPM montiored?

And also, how can you find out how much amperage the fan draws?

[Cricket]

Hi Jamiejc87,

If the fan has only 2 wires going to the Molex connector, then you won't be able to monitor the RPM. Fans that have 3 wires usually are 3 pin connector type, the 3rd wire is for RPM sensor.

Oops...sorry about this, I think I'm getting amps and watts mixed up. Only had 1 electronics class way back in high school...30 years ago .

Anyway, check the back of the fan, the label usually has the watt rating. The hard part is finding how much current is supplied at the motherboard fan headers. You sometimes have to really search the motherboard website really hard for this info.

2CoolTek will tell you how much amps and watts each fan it sells draws. Here are 2 different Sunon 60mm fans:
http://2cooltek.safeshopper.com/26/110.htm?692
http://2cooltek.safeshopper.com/26/37.htm?692

Compare them to these 2 Delta 60mm fans:
http://2cooltek.safeshopper.com/24/270.htm?692
http://2cooltek.safeshopper.com/24/266.htm?692

Cricket

[q2418130103p]

Ok thank you very much this clears up a lot for me. My fans are something like 3.24 watts (I’m guessing there, that's what I remember them saying on the back) with only two wires (ground and hot).

Buuuuuuuut.......... I have just ONE more question, I promise.

Is Molex simply the plastic type used for connectors, or is it a certain type. From what someone told me before, I figured that they were the 4 pin connector type coming from the PSU, but I might have miss understood them.

[Cricket]

Hi Jamiejc87,

Actually, Molex is the name of a company that makes the connectors. I guess we refer to the 4 pin connector as a Molex connector because maybe they were the first to come out with that type of connector.

Yes, it does refer to the 4 pin connector that is commonly used to connect the power supply cables to the drives.

Cricket

[q2418130103p]

YAY. I'm so glad they are called Molex, cause I have been spouting it out here like a buzz word. Good thing to cause the word is fun to say and makes me sound like I know what I'm doing. I have to learn to incorporate it into more conversations.

“Hi, I’m Jay, executive Molex buyer.”

Thank you for everything. You've been a huge help in my fan dilemma.

Thank you again,
Jay

[mike breck]

Hi Jamiejc87,

I agree with everything that Cricket has said apart from connecting the HSF fan to the PSU. I "personally" feel happier with mine being monitored by the mobo.

The reason for this is if the CPU stops working then you only have a short period of time before the heat can damage the CPU.

If the HSF is being monitored by the mobo or a program like MBM

http://mbm.livewiredev.com/

then you can set up an alarm to go off or get the system to shut down when the fan stops working. This, to me, is a good arrangement and outweighs any possible risk of the HSF damaging the fan header on the mobo. I've come across more people reporting that they have fried their CPU than damaging the mobo fan header.

You can, of course, spread the electrical load by connecting your case fans to the PSU.

Just my opinion.

[markkerr]

Thanks for the advice. I have connected the CPU/heatsink fan
to the mobo and both front and rear fans to the pwr supply!

Mark