[SOLVED] How do I put up my case fans?

Sep 6, 2019
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Hello!

I just finished building together my new little machine! I'm using a Fractal Define R5 case that comes with two already in build case fans (Fractal GP-14, 1x intake front/1x exhaust back). I kinda felt like buying a second front intake fan and that's why I got myself a Noctua NF-A14 PWM. The problem now is that the cable of it is too short to plug it into the mainboard, so I considered using it as my back exhaust fan and put the two fractal ones as the intake fans in the front.

I'm not so sure about how to do it, maybe I could get myself an extension cable for the noctua fan? What do you guys think, does it even matter which fan I use for what? I just feel like the Noctua fan is a better choice than the other two so maybe there's a "good" way to do it! :)

Thanks in advance for any answers!

Greetings
 
Solution
As far a fan performance itself goes, there is little difference from how you mix them. BUT there IS a difference in how they are plugged in.

The two Fractal Design fans are 3-pin type. If you check the wires from their motors there should be three - Black, Red and Yellow - and the connector on the end will have three holes. On the other hand, you say you have a PWM 4-pin fan from Noctua. Those two fan types require different methods of controlling their speeds, so they need to be connected to different fan headers so those headers can be configured differently. Thus I suggest you place the two Fractal Design 3-pin fans near each other (both at the front). Then you can connect both of them together to a single mobo fan header by using...

Paperdoc

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As far a fan performance itself goes, there is little difference from how you mix them. BUT there IS a difference in how they are plugged in.

The two Fractal Design fans are 3-pin type. If you check the wires from their motors there should be three - Black, Red and Yellow - and the connector on the end will have three holes. On the other hand, you say you have a PWM 4-pin fan from Noctua. Those two fan types require different methods of controlling their speeds, so they need to be connected to different fan headers so those headers can be configured differently. Thus I suggest you place the two Fractal Design 3-pin fans near each other (both at the front). Then you can connect both of them together to a single mobo fan header by using a SPLITTER (not a Hub) if you wish, or to two separate headers if you have three available. Place the Noctua at the back as exhaust, and connect it to its own header.

In case you have not yet noticed this, most fans have two arrows molded into their frames. One points through the fan and indicates the direction of air flow, so that's how you decide which way to mount the fan in an opening. The other points around the fan and indicates the direction of blade turning.

Now to fan header configuration in BIOS Setup. Most SYS_FAN or CHA_FAN headers these days offer you a choice of the method it uses to control the fan speed. It is called the MODE. So you must set a header to use Voltage Control Mode (aka DC Mode) if your fan is the older 3-pin type. (If you use PWM Mode for those, the fans will run full speed always.) For the Noctua PWM fan, set this header's option to PWM Mode. When you have made your adjustments to all the fan headers, remember to SAVE and EXIT to save your settings and reboot.
 
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Solution
Sep 6, 2019
9
0
10
As far a fan performance itself goes, there is little difference from how you mix them. BUT there IS a difference in how they are plugged in.

The two Fractal Design fans are 3-pin type. If you check the wires from their motors there should be three - Black, Red and Yellow - and the connector on the end will have three holes. On the other hand, you say you have a PWM 4-pin fan from Noctua. Those two fan types require different methods of controlling their speeds, so they need to be connected to different fan headers so those headers can be configured differently. Thus I suggest you place the two Fractal Design 3-pin fans near each other (both at the front). Then you can connect both of them together to a single mobo fan header by using a SPLITTER (not a Hub) if you wish, or to two separate headers if you have three available. Place the Noctua at the back as exhaust, and connect it to its own header.

In case you have not yet noticed this, most fans have two arrows molded into their frames. One points through the fan and indicates the direction of air flow, so that's how you decide which way to mount the fan in an opening. The other points around the fan and indicates the direction of blade turning.

Now to fan header configuration in BIOS Setup. Most SYS_FAN or CHA_FAN headers these days offer you a choice of the method it uses to control the fan speed. It is called the MODE. So you must set a header to use Voltage Control Mode (aka DC Mode) if your fan is the older 3-pin type. (If you use PWM Mode for those, the fans will run full speed always.) For the Noctua PWM fan, set this header's option to PWM Mode. When you have made your adjustments to all the fan headers, remember to SAVE and EXIT to save your settings and reboot.
I just placed the two Fractal fans at the front, connecting them to their own headers (cables are quite long). The noctua is now at the back, working as an exhaust fan. Now I just have to apply the stuff in BIOS and I think I'm settled for now, maaaybe I might replace the fractal fans, but don't think it's that necessary! Thank you very much for helping me out sir, appreciated!
 

Paperdoc

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You're welcome. As long as you can configure the headers for the 3-pin fans to use the older Voltage Control Mode, you should not need to replace them.

Here is a way to test whether your mobo headers CAN actually control the fan speeds. Basically you just need to open the case so you can watch the fans closely right as they start up on a reboot.

The NORMAL sequence on booting a system is that the mobo fan headers turn ALL of the fans on at full speed, to be sure they do actually start up. After a few seconds it gets readings from its temperature sensors and the automatic fan control system slows the fans down to whatever is needed for a cool system. So if EACH fan starts fast and then slows down after a short time, then each control system IS able to control its fan properly.
 
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Sep 6, 2019
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You're welcome. As long as you can configure the headers for the 3-pin fans to use the older Voltage Control Mode, you should not need to replace them.

Here is a way to test whether your mobo headers CAN actually control the fan speeds. Basically you just need to open the case so you can watch the fans closely right as they start up on a reboot.

The NORMAL sequence on booting a system is that the mobo fan headers turn ALL of the fans on at full speed, to be sure they do actually start up. After a few seconds it gets readings from its temperature sensors and the automatic fan control system slows the fans down to whatever is needed for a cool system. So if EACH fan starts fast and then slows down after a short time, then each control system IS able to control its fan properly.
So, all the fans started at full speed and automatically slowed down on their own. Switched SYS_FAN2 (Noctua) to PWM, both Fractals are on DC, as you told me. I'm just not sure about the low noise adapter for the noctua that reduces the max rpm to 1200 from 1500, won't it be an issue when gaming? And another question while I'm here, is the some good software I could use to keep track of my fans?
 
Sep 6, 2019
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I've checked the numbers for now and it's a bit surprising that the PWM fan is it around 900 rpm in idle mode, not doing anything basically, making the fan louder than I expected. Not sure if it's normal but putting the PWM fan on DC mode in BIOS actually makes him very quiet, around 600 rpm. Is there something I can do about that?
 

Paperdoc

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Yes, do NOT use the Low Noise Adapter in the wiring connections to the Noctua PWM fan. That little device is handy when you can NOT connect it to some mobo automatic control header and are forced to use it only connected to a full 12 VDC supply from the PSU with NO speed control. In that situation the adapter is a way to slow the fan permanently . All it is, is a resistor the reduces the voltage to the fan motor. BUT when the fan is connected to a mobo header that DOES change the fan's speed, the adapter interferes and basically prevents it ever from reaching its max speed. As you anticipate, that is exactly what you do NOT want when gaming and pushing max heat generation!

With that adapter removed, the mobo SYS_FAN header will set its speed according to the temperature measured by a sensor on the mobo. You should remember that, if you decide that the fan is too noisy and force it to slow down, you are reducing the heat removal by the fan and making your system run hotter. Also note that Noctua fans generally are among the quietest on the market, so any other fan would not be better for noise.
 
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Sep 6, 2019
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Hey, thanks a lot for your reply, appreciated! I've played with BIOS once again these past few days and I'm not yet sure how to set up the PWM fan (I've linked a picture of the settings I currently have). So far, PWM mode with smart fan enabled works the best, the fan curve is still the default one. Without smart fan it basically sets the voltage to a constant value of 7,2V. What do you think of the preset fan curve, should I adjust things a bit?




CHVMqyQ.png
 

Paperdoc

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You should check two things.

First, your photo shows the display for the CPU_FAN header. That does NOT show you anything about the SYS_FAN headers and their fans. If you want to see the speed either of the Noctua fan on one of those SYS_FAN headers, or of the Fractal fans on the other, you need to choose those headers to see their data.

Secondly, your photo for the CPU_FAN headers shows a place to specify the Temperature Source. For EACH of the SYS_FAN headers go to their screens and look for that item. Set those headers to use the MOTHERBOARD temperatures sensor, and not the CPU chip internal sensor. After making changes, remember to SAVE and EXIT.
 
Sep 6, 2019
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Hello,

so, I replaced the exhaust noctua fan with a new BeQuiet Silent Wings 3 pwm fan. I've tried to set up a proper temperature source for the fans in the BIOS, options being "System", "MOS", "CPU" and "Chipset". I've set up the temperature source to "System" for now, since "motherboard" is not choseable. At the moment I'm running the two intake fans on DC mode with 7.2V, running at about 600rpm constantly. I've set up a smart fan curve for my exhaust fan (100%-70C, 80%-60C, 60%-50C, 40%-40C). The only issue I see at the moment is that, since the fans have "system" as their temperature source, the RPM do not go higher than about 700 while gaming. To be honest, I'm still quite confused about how to set things up properly. I've also attached an image of my fan speeds/temperatures when under little load.




0nmSQz3.png
 

Karadjgne

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The reason your fans aren't going above @ 700rpm is because they do not need to.

System temps are pulled from somewhere on the motherboard. Meaning unless it's sitting next to something like a Sata controller and getting very hot, it's going to be pulling about case temps. Not cpu temps. Case temps usually run @ 30-40°C, maybe up to 50°C if you are unlucky. Your fan curve is set to not reach 100% until case temps reach 70°C.

Meaning you need to adjust the fan curves. Typically you'd still be at @ 40% duty cycle, which would be right around 700rpm ish on a 1500rpm fan.

If you change from System to CPU, your fan curves will be changed according to cpu temps, not system temps.
 
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Sep 6, 2019
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Thanks for your reply! I’ve now finally managed to set things up nicely, everything’s working according to plan. There is just one small issue that I still have.
The fans are bsolutely quiet in idle, the noise is barely noticeable under load, all good here. The only annoying thing is that there’s a weird noise coming out of the case from time to time, a kinda humming/vibrating noise that occurs in Intervalls of like two seconds..imagine an alarm clock beeping every seconds, that’s how the humming occurs. I’ve tried to find the cause of it but it’s been difficult so far, it’s not the case fans for sure, neither the chipset fan nor the gpu fans. I still have to check the cpu fan. What do you guys think is causing the humming noise? Any ideas? :(
 

Karadjgne

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Thousand ideas lol. It could be anything from a chunk of dust dislodged and caught on a fan blade, which changes the weight and pitch, setting the fan off balance. Could be one of the wires is barely a hair into the fans rotation, bouncing off the blades. Could be a fan with bad bearings. Or any number of other oddities.