Extreme case fan confusion

[Starshine]

Hello, it seems like I need the help of this great community here again

I'm just terribly confused about my case fans, my case is an Aerocool iCurve which has two pre-installed 12cm fans, one outtake at the back of the case and one intake right infront of the HDD cage, so far so good.

I added two generic (cheap, 5 bucks on Amazon each ) additional 12cm intake fans to the side of the case. I know I can't expect much from such cheap fans but the airflow is actually quite strong though my problem lies with the cabling.

All four fans, also the pre-installed ones come with two type of connections on their cables, one 4pin IDE style molex connection and one 3pin motherboard-style connector

My be quiet! PSU has special fan lines, black and white cables with these 3pin and 4pin molex pass-through connections and a sticker that explicitly states that no fan should be attached with both of its connectors.

Now the crazy weird thing, the pre-installed fans always seem to run at the same decent speed, all fine. Though my additional fans rotate fairly slowly no matter if I use the 4pin or 3pin connection.

If I now ignore the warning sticker and connect each of the four fans with both, 3pin and 4pin and only then! the speed of the extra fans suddenly doubles if not triples

I'm completely lost here because this doesn't make any sense to me, I only want one of these extra fans run at full speed while the other should run slower though I can't understand why that happens, there's no fan controller in this case and neither of them is connected to the motherboard all go directly to the PSU so it would be nice if some of the pros here could shed some light on this

Thanks in advance!

 

[Conumdrum]

There are two different connectors. You buy the plugs, pins, and the required crimping tool to make the match. No big deal for a case modder. And you might of bought 4 pim PWM fans. Oops............

Performance PC's has all you need.

And you should learn about Molex and the smaller molex. Tons of info on the net. Become one with google and search terms.

 

[Starshine]

Thanks for the reply Conumdrum!

I admit your post hit me cold since I'm a newb but I'm willing to learn so I will try to go in detail with some things:

I googled before I posted here and all it told me was that the molex 4pin connections are used if you want the fan to spin a max RPM and the other 3pin smaller connections are for slower RPM/fan controller/motherboard dunno if that's right, a bit clarification on this would be nice.

My PSU supplies all kinds of connections so I have both ways to connect the fans already present my problem is only that they either ran all at max speed if I plug in all the cables disregarding the warning on my PSU or all at a slower speed when I want only the one next to the GFX card run at full speed :/

Should I simply buy a fan controller or is there a way to do this with cabling alone?

 

[JackNSally]

Sounds like the fan(s) you want to run at full speed should be plugged into a regular molex connector. The others can be plugged into the special fan connections.

 

[Conumdrum]

3 pin fans are controlled by varying the voltage. And has a yellow wire typically the RPM signal if you want to monitor it.

The big 4 pin molex is the same when it comes to fans. Except the one you show has 5V Gnd Gnd 12V. and no RPM wire since it's off the PSU. And not adjustable. I have used that for fans. The fan only uses the 12 and gnd for wires.

So yea, to control 3 pin pan, you'll want a fan controller. Typical fan controllers use the small 3 pin connectors. Millions of fan controllers out there, don't buy a junk one. Let us know what you come up with.

 

[janat08]

You should try reverting one of fans so that you have 2 intake, and 2 outtake fans. If your case is airtight (doesn't have iron meshes, or any other openings), the fans may not be working on at full power, because of high air pressure inside.

 

[janat08]

You could also take out front disk drive slot closings, so that air could come out that way.