Pins on fan

[Ace3891]

Hello, it's my first build so please bear with me if the question is silly.

I'm looking at the manual for my psu and the picture it has for connector for the fans have only 3 pins, but the ones for the fans on my case are 4, so is it ok if i just use the 4 pins that according to manual is for peripheral? Thanks.

[jlreich]

Yes that's fine. Usually if the fans have LED's it will have the 4pin molex connector so it can get the needed power for the LED's.

Also many fans come with a 4pin adapter to allow you to plug it in a molex connector in the case you don't have any free fan headers on your motherboard.

If your fans don't have LED's then you can plug them into any unused 3pin fan header you can find on the motherboard. Most motherboards have three or four. 1 for the CPU, 1 for the NB fan, and one or maybe 2 for case fans.

If your PSU has connectors marked as FANS ONLY it is so the PSU can control the RPM's of the fans according to need. I don't use like let the PSU control my fans. In fact I don't let anything control my fans as I like them to run full out all the time.

[Ace3891]

ok, thanks a bunch
i guess i'm gonna be connecting the four pins, since the only 3 pin on the mb mark sys fan is a little far for the cords

[Whyzman]

It is necessary for the CPU fan to be connected to the motherboard header. Most new motherboards use RPM sensing to determine that the CPU is being cooled before they will continue through the boot process.

However, you can use the molex connectors for even the 3 pin CPU motherboard header with an adapter that allows it to read the RPMs yet get its 12V power directly from the power supply.

Personally, after a suggestion from long time member Rick, I use adapters for all fans preferring not to have the power for them come through the motherboard. Yet, I can monitor their RPMs through the BIOS if I so desire. As jlr points out, I too pretty much let the fans run full out.

If you'd like a look at the adapters...here: http://www.directron.com/3splitter.html