Sign in with
Sign up | Sign in
Your question
Closed

4 - to - 3 pin adapters for case fans?

Last response: in Components
Share
May 27, 2010 7:51:17 PM

As per my previous topic, of which the responses were highly informative and I thank everyone for chiming in, it would seem that I have a mild dilemma.

Firstly, my rig:
-Asus P6X58D Premium
-Intel i7 930 Bloomfield
-HIS Radeon HD5870
-Case: NZXT Tempest Evo
-Heatsync: Noctua Ultimate 120 SE2 (2 fans)

If I've read the previous threads correctly:

-The 4 pin headers' voltage is controlled by the mother board. The mobo will automatically increase or decrease wattage based off temperature.

-The 3 pin headers are not automatically controlled by the mother board. The only way to regulate them is through software (such as PCProbe, etc.).

Now, my mobo has 2x 3pin, 1x 4pin, and 1x 4pin cpu fan. However, all the fans that came with my heatsyn and case use 3-pin fan cables. So now I'm trying to determine the case scenario. Pun intended. :sol: 

I'd like AS LITTLE monitoring on my end as possible. Thus, I'm thinking that it may be best to make use of both 4-pin connected such that my mobo can automatically account for a few fans.

I've already purchased the 3 pin Y splitters. Now I need to know if there are 4-to-3 pin fan adapters. But not just to supply power, but to control voltage as well. Can a 3 pin fan be plugged into an adapter which plugs into a 4 pin header such that the 3 pin fan acts like a 4 pin fan? In other words, is there any way to get my 3pin fans's voltage regulated by the mobo rather than software?

Thanks guys,
Daniel

More about : pin adapters case fans

May 27, 2010 7:59:56 PM

Just offset the connector... It still only goes in one way with the way the tabs are located.

Bios usually has options on how the fans are regulated depending on what (3or4pin) fan you have.
May 27, 2010 8:05:59 PM

r-sky said:
Just offset the connector... It still only goes in one way with the way the tabs are located.

Bios usually has options on how the fans are regulated depending on what (3or4pin) fan you have.


R-Sky,

I believe we missed the point of the post. I understand that I can offset the 3-pin connector, but I WANT the benefits of using 4 pins.

Thus, a []FAN[]---(3pin to 4 pin adapter)---[]4-Pin Header[]

AND the fan gains the benefits of power modulation associated with 4 pin fans.
Related resources
May 27, 2010 8:08:17 PM

Buy ew fans
a b ) Power supply
May 27, 2010 9:49:04 PM

Exactly. All the adapter is going to do is drop the 4th pin for you.
a c 243 ) Power supply
May 27, 2010 11:08:39 PM

Chapter 4 page 6 of the manual
May 28, 2010 3:28:42 AM

danforz said:

-The 4 pin headers' voltage is controlled by the mother board. The mobo will automatically increase or decrease wattage based off temperature.

-The 3 pin headers are not automatically controlled by the mother board. The only way to regulate them is through software (such as PCProbe, etc.).


lol what kind of rubbish is this?

the 4th pin connector usually work in conjunction with the PWM function of the fans (if you have PWM fans).

most DC fans are 3 pin, they can be automatically controlled by the motherboard through voltage regulations, lower voltage = lower rpm, higher voltage = high rpm. this is mostly just a BIOS setting, as all my fans in my case are 3 pin, I just set automatic fan control to "DC/Voltage" in my BIOS, as opposed to the default "PWM". my 3pin fans run at varied speed according to temperature-adjusted by BIOS, no need for 4pin adapter, there is no such thing.

they only thing close you are going to get to a 4-3pin converter is a molex-3pin, which is entirely different thing.
a b ) Power supply
May 28, 2010 10:15:20 AM

What you need is a fan controller that caters for the 4 pin PWM fans and the only one that I have seen was from akasa but I've never found it in stock anywhere.
a b ) Power supply
May 28, 2010 12:08:04 PM

arterius2 said:
lol how would that sovle anything?


Well it's got 12v 7v and 5v connections to control the fan speed (high, medium and low), which is better than a normal 4pin molex - 3 pin (which is either 12v or 5 v) and it's cheaper than a fan speed controller.

Or you can try this

http://www.hardwaresecrets.com/article/496
May 28, 2010 2:38:29 PM

LOLOLOLOL why people still don't get this, you DONT NEED TO BUY ANYTHING to control fan speed with 3pins, motherboard can already do this, all you need is to change a BIOS setting and its done.
a b ) Power supply
May 28, 2010 3:17:11 PM

arterius2 said:
LOLOLOLOL why people still don't get this, you DONT NEED TO BUY ANYTHING to control fan speed with 3pins, motherboard can already do this, all you need is to change a BIOS setting and its done.

That does not work for the 4 pin fans that I'm using, they all spin at 100% regardless of BIOS settings.
May 28, 2010 3:46:21 PM

Mousemonkey said:
That does not work for the 4 pin fans that I'm using, they all spin at 100% regardless of BIOS settings.


if you have 4 pin PWM fans and using it on 3pin motherboards, they will obviously spin at 100%, but 3 pin fans can be plugged into 4 pin sockets and be controlled via voltage.

OP states: "-The 3 pin headers are not automatically controlled by the mother board. "

which is wrong, all my fans in my mobo are 3pins and they are controlled automatically by the motherboard depending on cpu load and temperature.
a b ) Power supply
May 28, 2010 3:55:49 PM

arterius2 said:
if you have 4 pin PWM fans and using it on 3pin motherboards, they will obviously spin at 100%, but 3 pin fans can be plugged into 4 pin sockets and be controlled via voltage.

OP states: "-The 3 pin headers are not automatically controlled by the mother board. "

which is wrong, all my fans in my mobo are 3pins and they are controlled automatically by the motherboard depending on cpu load and temperature.

My bad, I was doing a bit of to'ing and fro'ing whilst looking at this thread and somehow got it into my head that the OP was asking about 4 pin fan controllers. Doh!
a b ) Power supply
May 28, 2010 8:57:57 PM

Here is how these fan connections and controls are supposed to work.

The standard 3-pin cooling fan (case or CPU) has 3 wires to its connector - Black on one end for Ground, Red in the middle for + 12 VDC (but it varies for control), and Yellow on the other end to carry a pulse signal FROM the fan motor back TO the mobo for measuring fan speed. Fan speed is controlled by the mobo which varies the + VDC value (12 or less).

A standard 4-pin fan has 4 wires: Black on one end for Ground, Yellow next to it for + 12 VDC ("always" 12 VDC), Green for the speed pulse signal, and Blue on the other end for the PWM (different) pulse signal used to control speed. In this system control of fan speed is actually done locally within the fan motor case by a small circuit that uses the PWM signal to control how much of the + 12 VDC supply is fed to the motor.

The connectors for the fans and the 4-pin pinouts on the mobo are cleverly designed so that the first 3 pins are exactly the same as those on a 3-pin mobo pinout, AND mechanically arranged so that you can plug in EITHER a 3-pin or 4-pin fan. But you can only plug in either fan ONE way so that the first three pins always mate up with the correct fan leads, and the 4th pin can only connect to the correct lead of a 4-pin fan.

Now, this gives us options. If you plug a 4-pin PWM style fan into a 4-pin mobo pinout, the mobo circuit sends the right 4 signals on those pins, and it works. In this case pin #2, the + VDC supply, is always + 12 VDC, and the motor's internal circuit uses the PWM signal on the 4th line to achieve control. However, if you plug a 3-pin fan into that mobo 4-pin pinout, the mobo CAN change what it sends out of the connector: now it needs to not bother sending out any PWM signal on the 4th pin, BUT it does need to the supply a VARYING DC voltage on pin #2 to achieve fan speed control. So, how can this be done? Some mobo's have a spot in the BIOS Setup screens where you must manually specify whether the fan you have plugged into that pinout is 3-pin or 4-pin. Set this wrong and basically your fan will always run at full speed. Some mobos appear simply to assume that you will ONLY use the correct fan type, so you MUST use a 4-pin fan on a 4-pin pinout. I don't know whether there are any mobos smart enough to just figure it all out by themselves - anyone around here ever see that?

I am not exactly sure what happens if you plug a 4-pin fan into a 3-pin pinout on a mobo. I expect that it will work because the (varying) +VDC supply, Ground and Speed lines all are connected. I'm guessing (does anyone here KNOW?) that a PWM fan given a variable DC supply and NO PWM signal to use will simply run at variable speed according to the voltage available to the motor. Not optimal at all, but maybe it works - I'm not sure.

So, OP, your mobo was designed for the ideal that the CPU fan and ONE case fan will be the 4-pin PWM type, and the other case fans, if any, will be 3-pin. However, you have only 3-pin fans to use. Go ahead and use them. They will plug into both 3-pin and 4-pin mobo connection points. When plugged into 4-pin connectors, one of three things is possible:
1. You look in the BIOS and find that (although I don't see this in the mobo manual) there actually is a place in the CPU cooler control system to specify which fan type you have connected, and there's a similar place for the one 4-pin case fan output.
2. You find no such adjustment possible, and your 3-pin fans on the 4-pin outputs simply run at full speed all the time.
3. You get lucky and wonderfully the mobo senses the right way to do all the fans and does actually achieve fan speed control all around.

Of course, the fourth option is that you actually go out and buy two 4-pin fans to use for the CPU cooler and one case fan.

Remember that to accomplish fan speed control based on measured temperatures, the BIOS must be set to do the automatic speed control. Most BIOS's come set that way by default and you can defeat that and set the fan speed to some fixed value or to full speed if you choose. Just make sure it is allowed to do its auto control thing. By the way, the CPU temperature displayed by the BIOS and used for CPU cooling fan control is picked up by a sensor built into the CPU chip and fed to the mobo on one of the CPU's pins. On the other hand, the BIOS displays and uses as "System Temperature" what is measured by a different sensor built into the mobo itself. This is one good reason that you MUST connect the right fan to the right mobo output port. Mix them up and fan speed will be controlled by the wrong temperature sensor!
June 1, 2010 10:20:30 PM

Paperdoc said:
Here is how these fan connections and controls are supposed to work.

The standard 3-pin cooling fan (case or CPU) has 3 wires to its connector - Black on one end for Ground, Red in the middle for + 12 VDC (but it varies for control), and Yellow on the other end to carry a pulse signal FROM the fan motor back TO the mobo for measuring fan speed. Fan speed is controlled by the mobo which varies the + VDC value (12 or less).

A standard 4-pin fan has 4 wires: Black on one end for Ground, Yellow next to it for + 12 VDC ("always" 12 VDC), Green for the speed pulse signal, and Blue on the other end for the PWM (different) pulse signal used to control speed. In this system control of fan speed is actually done locally within the fan motor case by a small circuit that uses the PWM signal to control how much of the + 12 VDC supply is fed to the motor.

The connectors for the fans and the 4-pin pinouts on the mobo are cleverly designed so that the first 3 pins are exactly the same as those on a 3-pin mobo pinout, AND mechanically arranged so that you can plug in EITHER a 3-pin or 4-pin fan. But you can only plug in either fan ONE way so that the first three pins always mate up with the correct fan leads, and the 4th pin can only connect to the correct lead of a 4-pin fan.

Now, this gives us options. If you plug a 4-pin PWM style fan into a 4-pin mobo pinout, the mobo circuit sends the right 4 signals on those pins, and it works. In this case pin #2, the + VDC supply, is always + 12 VDC, and the motor's internal circuit uses the PWM signal on the 4th line to achieve control. However, if you plug a 3-pin fan into that mobo 4-pin pinout, the mobo CAN change what it sends out of the connector: now it needs to not bother sending out any PWM signal on the 4th pin, BUT it does need to the supply a VARYING DC voltage on pin #2 to achieve fan speed control. So, how can this be done? Some mobo's have a spot in the BIOS Setup screens where you must manually specify whether the fan you have plugged into that pinout is 3-pin or 4-pin. Set this wrong and basically your fan will always run at full speed. Some mobos appear simply to assume that you will ONLY use the correct fan type, so you MUST use a 4-pin fan on a 4-pin pinout. I don't know whether there are any mobos smart enough to just figure it all out by themselves - anyone around here ever see that?

I am not exactly sure what happens if you plug a 4-pin fan into a 3-pin pinout on a mobo. I expect that it will work because the (varying) +VDC supply, Ground and Speed lines all are connected. I'm guessing (does anyone here KNOW?) that a PWM fan given a variable DC supply and NO PWM signal to use will simply run at variable speed according to the voltage available to the motor. Not optimal at all, but maybe it works - I'm not sure.

So, OP, your mobo was designed for the ideal that the CPU fan and ONE case fan will be the 4-pin PWM type, and the other case fans, if any, will be 3-pin. However, you have only 3-pin fans to use. Go ahead and use them. They will plug into both 3-pin and 4-pin mobo connection points. When plugged into 4-pin connectors, one of three things is possible:
1. You look in the BIOS and find that (although I don't see this in the mobo manual) there actually is a place in the CPU cooler control system to specify which fan type you have connected, and there's a similar place for the one 4-pin case fan output.
2. You find no such adjustment possible, and your 3-pin fans on the 4-pin outputs simply run at full speed all the time.
3. You get lucky and wonderfully the mobo senses the right way to do all the fans and does actually achieve fan speed control all around.

Of course, the fourth option is that you actually go out and buy two 4-pin fans to use for the CPU cooler and one case fan.

Remember that to accomplish fan speed control based on measured temperatures, the BIOS must be set to do the automatic speed control. Most BIOS's come set that way by default and you can defeat that and set the fan speed to some fixed value or to full speed if you choose. Just make sure it is allowed to do its auto control thing. By the way, the CPU temperature displayed by the BIOS and used for CPU cooling fan control is picked up by a sensor built into the CPU chip and fed to the mobo on one of the CPU's pins. On the other hand, the BIOS displays and uses as "System Temperature" what is measured by a different sensor built into the mobo itself. This is one good reason that you MUST connect the right fan to the right mobo output port. Mix them up and fan speed will be controlled by the wrong temperature sensor!


Thank you, and everyone else, for your informative responses. I have a few Y splitters on the way so I'll just plug everything into the mobo and see what happens. Currently they are all attached to the PSU directly and the sound isn't really a problem for me. So worse comes to worse, I can just leave it like that and take a slight $ hit in an electric bill. Thanks again!
!