clearifications about this Molex to 4 pin fan adapter ..

ateeb123

Reputable
Nov 15, 2015
17
0
4,510
Hello Guys,

I am considering to buy this Molex to PWM fan adapter, so i need to know, if all of these will provide PWM functionality.

What i think how it should work, " the 4 pin fan will provide the PWM signal and eveyother fan connected to other 3pin connectors will adjust their speeds according to the speed of 4pin fan".

Please correct me if i am wrong, and enlighten me on other stuff according to this adapter.

Btw, to be used in DELL T3500..

Cheers,
Ateeb.
 
Solution
The adapter in question is pretty straightforward. It simply adapts a single 4-pin PWM connector to allow up to 5, 4-pin PWM fans to receive the PWM signal from it, and 1, 4-pin PWM fan to report tachometer signal back to the fan controller, taking power from a 4-pin Molex.

If you use 4-pin PWM fans with this adapter, they will all be given the same PWM control signal, so should all run at the same relative speed.

If you use non-PWM fans with this adapter, they will most likely just run at full speed.

The reason 4 of the 5, 4-pin connectors are being labelled as 3-pin is, they don't have the tachometer pin in them because you can only read the tachometer from one of the fans, the one with the 4th wire going to it.

Aeacus

Titan
Ambassador
Hmmm... interesting fan splitter.

Looking from it's product pics, it can only control 4-pin fans via PWM where 3-pin fans connected to it will run 100% all the time. And if you were to connect 5x 4-pin fans to it, all 5x fan will run in sync. Oh, only the 1st fan RPM feed is fed back to the MoBo.

To put it short: it should work as advertised when you connect only 4-pin fans to it.
 

ateeb123

Reputable
Nov 15, 2015
17
0
4,510


So if i were to connect 5x 4-pin PWM fans like thishttp:// to the three pin connectors of the aformentioned splitter, all of them would spin at the frequency of CPU or the fan connected to 4pin header of the splitter?
AND I WILL BE ABLE TO CONTROL THE RPM OF FAN CONNECTED TO 4-PIN HEADER OF THE SPLITTER USING SPEEDFAN?
 

Aeacus

Titan
Ambassador
The TITAN IP55 92mm fan you linked is 3-pin fan and it will spin at 100% (3000 RPM), without any hope of controlling it's speed, if you were it to connect that to PWM splitter you linked above.

For 4-pin fan, look towards Arctic F12 PWM (120mm),
amazon: https://www.amazon.com/dp/B00H3T1KBE

or Arctic F9 PWM if you want 92mm fans,
amazon: https://www.amazon.com/dp/B00H3SVWF4

Also, SpeedFan can not control CPU_FAN header on MoBo. If your MoBo has SYS_FAN header which is 4-pin and supports PWM then you can use SpeedFan to control that.
 
The adapter in question is pretty straightforward. It simply adapts a single 4-pin PWM connector to allow up to 5, 4-pin PWM fans to receive the PWM signal from it, and 1, 4-pin PWM fan to report tachometer signal back to the fan controller, taking power from a 4-pin Molex.

If you use 4-pin PWM fans with this adapter, they will all be given the same PWM control signal, so should all run at the same relative speed.

If you use non-PWM fans with this adapter, they will most likely just run at full speed.

The reason 4 of the 5, 4-pin connectors are being labelled as 3-pin is, they don't have the tachometer pin in them because you can only read the tachometer from one of the fans, the one with the 4th wire going to it.
 
Solution

Paperdoc

Polypheme
Ambassador
bigpinkdragon286 is exactly right. The four "3-pin" outputs are simply 4-pin outputs missing their Pin #3 because they can NOT be allowed to send their fans' speed signals back. This device is a plain 4-pin fan HUB that gets power for all fans from a PSU 4-pin Molex output connector.
 
These adapters are very handy. I use them when I want to run fans that will draw more amperage than the fan controller can safely supply. There's no way you're going to attach enough fans using one of these to overload a Molex connection.

The only possible downside I can see is if your fan controller produces a very weak PWM signal. I've read about it but not experienced it personally that too many fans on a single PWM signal and they may not function correctly with the PWM signal.