3pin to 4pin converter for CPU fan?

[pjyelton4476]

I would like to run smart fan controls for my CPU fan. The motherboard has a four pin male CPU_PWR connector but every fan I can possibly find that will fit my board (socket 754) are all 3-pin power connectors.

When connecting my 3-pin to this 4-pin I can read the RPM's just fine but the Smart Fan doesn't work. I called up the manufacturer of my motherboard and they say I need to have a 4-pin fan for Smart Fan controls.

I did some searching but I don't see any 3-pin to 4-pin adapters unless they are the kind that converts to the PSU instead of the motherboard. Does such a thing exist? If not, any other ideas?

 

[coolpurplefan]

3 pin to molex?

 

[Shotgoon]

Do you have an Epox? I have an NPA3Ultra or whatever and it has 4 pins and says the same thing. The first 2 pins are + and -, the third is speed reading and the 4th is speed control. It's not possible for an adapter to exist for this. I picked up an Alpine 7 for use on my Athlon 64 3000+ (Winchester 1.8 OCed to 2.475) and it seems to cool about 5C better at full load and just a few C better at idle.

The 4 pins are mostly seen on LGA775 systems so finding a S939 compatible HSF combo can be hard. From what I've read, the 4 pin system is called pulse width modulation and what it does is instead of apply constant voltage, it does it in bursts and is more efficient. You could use the Alpine 7 like me, or the Zalman 9500AT if you want beefier cooling and are able to get an extra S939 bracket for it. I believe Cooler Master also has the Hyper 6 that has 4 pins. Other than that, I don't really know of any 4 pin coolers worth looking at for socket 939 with 4 pins.

 

[pjyelton4476]

How did you guess it was an Epox?

Does that Alpine 7 come with 4 pins? I ask because I recently bought an Arctic Cooling ACS64U online when the specs said it was 4 pins even though when I received it the fan only had 3 pins.

Also, for the Alpine 7, does it easily just place onto a socket 754 or would there be more work involved like brackets etc? I'm really not sure what the difference between the 754 socket and the 939 socket are if any.

Thanks for the help by the way!

 

[Shotgoon]

Yeah the Alpine 7 has 4 pins. It's the same as the Alpine 64 but comes with an extra bracket for LGA775. Socket 754 and 939 use the exact same mounting bracket so any cooler that works with one will work with the other. Price is pretty cheap too, was like $14 on Newegg, after shipping $19 of course but at least you can control the fan speeds. It's very easy to install too.

 

[Zepper]

Welcome to the AT Forums if I haven't caught you before.

Would be nice to know what mobo you're talking about so we don't have to diagnose in the dark!

Most fans have only three wires: one for +12V, one for ground, and the third will be either speed sensor or speed control. Fans with BOTH speed sensor and speed control wires are VERY rare. Most standard 3-pin (with speed sensor wire) CPU fans will be controlled in steps relative to the CPU temp as reported by the mobo health chip. The pinout for the connector should be in your manual (you did read your mobo manual from stem to stern before starting your build, didn't you??? Including the connector diagrams? Just connect the correct wires to the correct pins - if your mobo really has a weird CPU fan connector then it should come with an adapter and not expect you to provide one. According to an Epox mobo manual that shows a 4-pin connector, a regular 3-pin connector will also fit - it's obvious from the diagram... (Tempted to throw the D-word in again.)

Now if this 4 pin CPU_PWR is square (2x2) then that is not for the fan at all. It is for a power lead from the PSU (2 yellow/2 black wires). Any connector that is for a CPU fan will be marked CPU_FAN - do not attempt to connect a fan to the CPU_PWR connector!!! This power wire from the PSU is required for most mobos these days. The CPU fan connector will be marked CPU_FAN - NOT CPU_PWR...

OP,
. If you have been talking about the 4-pin connector that's like the ATX power socket, then allow me to toss in a "Duuuuuh" here and send you to http://www.mechbgon.com to read his New Builder's Guide before you hurt something or yourself...

.bh.