[SOLVED] Daisy chaining two (or more) fans - Molex, Molex, 3pin

Feb 17, 2021
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I hope the title was clear, I'm planning on connecting one fan into a port on the motherboard (z490) and running the molex that hangs off of it to the second case fan.
Will this allow me to adjust both fans, in terms of RPM?
Or will it cause the fan connected to the first one through the Molex connector to run at full speed (whilst allowing me to adjust the first fan's speed)?

Thanks in advance!
 
Can you also try to draw up how you think - why you're adding Molex into the mix?

If the fans aren't too big (in terms of wattage) you should be able to connect two fans on a fan controller. However - only one fan will be able to control the rpm, while the second fan will follow the first but won't run with exact same rpm. You need the fans to be of the same model.

In such setup, the gnd and +voltage will be connected together, but only feedback from first fan will be connected. Feedback from second fan should not be connected.
 
Feb 17, 2021
31
1
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I depends on the header you connect them to.
If the header is controllable....both fans will be.
If the header is full speed...both fans will be.
First fan is getting plugged into a cha_fan2 port and the molex cable that runs off of that will go to power the second case fan... sooo I'm guessing controllable, right?
 
Can you also try to draw up how you think - why you're adding Molex into the mix?

If the fans aren't too big (in terms of wattage) you should be able to connect two fans on a fan controller. However - only one fan will be able to control the rpm, while the second fan will follow the first but won't run with exact same rpm. You need the fans to be of the same model.

In such setup, the gnd and +voltage will be connected together, but only feedback from first fan will be connected. Feedback from second fan should not be connected.
 

Zerk2012

Titan
Ambassador
If I get this right your using 2 fans that have a motherboard fan connector and a Molex power connector.
Plugging one fan into the motherboard and the other into the Molex on the connected fan.

Both should run the same speed is all I can say with the information provided.
 
Feb 17, 2021
31
1
35
0
Can you also try to draw up how you think - why you're adding Molex into the mix?

If the fans aren't too big (in terms of wattage) you should be able to connect two fans on a fan controller. However - only one fan will be able to control the rpm, while the second fan will follow the first but won't run with exact same rpm. You need the fans to be of the same model.

In such setup, the gnd and +voltage will be connected together, but only feedback from first fan will be connected. Feedback from second fan should not be connected.
Hey guys, sorry laptop died on me, so instead of waiting for it to power up and read replies I decided to test it out :p

So plugging the first fan (3 pin) allowed me to adjust the fan speed but since the second fan was connected to the first by the molex cable I couldn't adjust it in BIOS. It was just running!

Either way it works for my negative pressure case system!

Thanks for everything guys!
 
Feb 17, 2021
31
1
35
0
Can you also try to draw up how you think - why you're adding Molex into the mix?

If the fans aren't too big (in terms of wattage) you should be able to connect two fans on a fan controller. However - only one fan will be able to control the rpm, while the second fan will follow the first but won't run with exact same rpm. You need the fans to be of the same model.

In such setup, the gnd and +voltage will be connected together, but only feedback from first fan will be connected. Feedback from second fan should not be connected.
Hye thanks for the advice! The case is on the smaller side and in order to cable manage nicely I was going to connect the front and back case fans together :)
Wasn't sure it was going to work , hence the forum!
 

Zerk2012

Titan
Ambassador
Hey guys, sorry laptop died on me, so instead of waiting for it to power up and read replies I decided to test it out :p

So plugging the first fan (3 pin) allowed me to adjust the fan speed but since the second fan was connected to the first by the molex cable I couldn't adjust it in BIOS. It was just running!

Either way it works for my negative pressure case system!

Thanks for everything guys!
Since you have a 3 pin fan it will depend on the motherboard. If your motherboard will allow you to change the speed to the fan it will do it by cutting the voltage down to say 9 volts instead of 12 volts for a example.

That should be putting the 9 volts also through the molex on that fan so plugging the 2nd fan into that molex should make it run the same speed.
 
Feb 17, 2021
31
1
35
0
Since you have a 3 pin fan it will depend on the motherboard. If your motherboard will allow you to change the speed to the fan it will do it by cutting the voltage down to say 9 volts instead of 12 volts for a example.

That should be putting the 9 volts also through the molex on that fan so plugging the 2nd fan into that molex should make it run the same speed.
Z490 - Asrock. Anywhere in the manual where I can see if it does that? :)
 

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