What is this fan cable used for?

[m150]

I just bought an ID Cooling SF12025 fan and found this cable in the box... can you please advise what it is? And how to use it? Thanks.

 

[m150]

I'm having 2 fans: 1 with 3-pin (Rear Exhaust fan), 1 with 4-pin PWM (CPU Cooler Fan). Can I plug these fans into this cable, then plug this cable into the CPU_Fan header on my motherboard (Gigabyte Z370XP-SLI)? Will both fans' speed be regulated by the CPU temp or the rear fan will always run at max speed? Thanks.

 

[Saga Lout]

MERGED QUESTION
Question from m150 : "What is this fan cable used for?"

I just bought an ID Cooling SF12025 fan and found this cable in the box... can you please advise what it is? And how to use it? Thanks.

Please try not to double-post.

It looks like a 2-to-1 adapter, so you can run two fans from a single fan header on a motherboard or fan controller.

The reason one pin is missing is because you don't want a tachometer signal from more than one fan being seen by the fan controller, or you'll get bad readings. So, if you use the adapter, the plug with the four pins is the one which will report fan speed, while the one with three pins will not.

 

[m150]

Please try not to double-post.

It looks like a 2-to-1 adapter, so you can run two fans from a single fan header on a motherboard or fan controller.

The reason one pin is missing is because you don't want a tachometer signal from more than one fan being seen by the fan controller, or you'll get bad readings. So, if you use the adapter, the plug with the four pins is the one which will report fan speed, while the one with three pins will not.

Thanks for merging - the browser is not responding and I have to refresh the page. Can you please help with this question? Thanks.

I'm having 2 fans: 1 with 3-pin (Rear Exhaust fan), 1 with 4-pin PWM (CPU Cooler Fan). Can I plug these fans into this cable, then plug this cable into the CPU_Fan header on my motherboard (Gigabyte Z370XP-SLI)? Will both fans' speed be regulated by the CPU temp or the rear fan will always run at max speed? Thanks.

 

[bigpinkdragon286]

Apologies, was out of the house all day.

3-pin fan speeds are usually controlled by voltage levels, while 4 pin fans are usually regulated via duty cycle, hence the PWM or (Pulse Width Modulation).

I'm going to go with, the fans should work together but are not compatible. The 3-pin fan should function at full speed in a PWM situation, since it has no method of working with any PWM signal being fed to it. Probably best to get matching PWM fans, if that's the method the fan controller is going to use. Some motherboards let you choose between PWM or Voltage control, but this is very hit or miss and also you find mixes of fan controllers on the same motherboard, where some are not controlled at all, some are PWM only, and maybe one or two are PWM or Voltage control, but never both types of control at the same time, as that isn't possible. Of course, voltage control isn't likely to work for your PWM fans, so you're going to have to decide which you want to go with. Might as well pick PWM, as that's the current standard, and just upgrade all of your fans you want to be controlled to that. You wouldn't need to upgrade any fans you don't mind running at full speed.

And of course, there is always the caveat that, if you go totally overboard and buy crazy powerful fans that blow hundreds of CFM of air, you may over stress the fan controller. There are limits, and having more than one fan on the same controller just adds to it. You can see the power draw of your fans on the back, usually on the backside of the hub where the motor mounts.

 

[m150]

Apologies, was out of the house all day.

3-pin fan speeds are usually controlled by voltage levels, while 4 pin fans are usually regulated via duty cycle, hence the PWM or (Pulse Width Modulation).

I'm going to go with, the fans should work together but are not compatible. The 3-pin fan should function at full speed in a PWM situation, since it has no method of working with any PWM signal being fed to it. Probably best to get matching PWM fans, if that's the method the fan controller is going to use. Some motherboards let you choose between PWM or Voltage control, but this is very hit or miss and also you find mixes of fan controllers on the same motherboard, where some are not controlled at all, some are PWM only, and maybe one or two are PWM or Voltage control, but never both types of control at the same time, as that isn't possible. Of course, voltage control isn't likely to work for your PWM fans, so you're going to have to decide which you want to go with. Might as well pick PWM, as that's the current standard, and just upgrade all of your fans you want to be controlled to that. You wouldn't need to upgrade any fans you don't mind running at full speed.

And of course, there is always the caveat that, if you go totally overboard and buy crazy powerful fans that blow hundreds of CFM of air, you may over stress the fan controller. There are limits, and having more than one fan on the same controller just adds to it. You can see the power draw of your fans on the back, usually on the backside of the hub where the motor mounts.

Thanks a lot for your thorough answer. My mainboard's fan header does support both PWM & voltage regulation and allow me to choose it in BIOS. What if I set the fan header to use voltage control, and connect both my 3-pin and 4-pin fan to that header. Will the 4-pin fan run at max speed, or it will vary based on temperature? Thanks again.

 

[bigpinkdragon286]

If you set your fan header to control the speed via voltage control, both fans should support that. It's not ideal, but it should work for now without replacing the rear fan.

The reason voltage control is no longer the standard is because it is inefficient and doesn't support the fine speed gradations that PWM does. It often results in fans running faster than they need to.

 

[m150]

If you set your fan header to control the speed via voltage control, both fans should support that. It's not ideal, but it should work for now without replacing the rear fan.

The reason voltage control is no longer the standard is because it is inefficient and doesn't support the fine speed gradations that PWM does. It often results in fans running faster than they need to.

Great thanks. I'll temporarily use it this way until replacing a new fan.