Question Fan connectors Asus Z490

chegalhavara

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May 7, 2016
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Hello guys

My Specs:
I7 10700K @ 5.0Ghz
EVGA RTX 3070 XC3 Ultra
Asus Rog Strix Z490-F Gaming
G Skill Ripjaws V 3000Mhz 16Gb
NZXT Kraken X52
Seasonic Focus+ Plus 750 Platinum
Cooler Master CM 690 III

So i upgraded from a 6700K to a 10700k and from an Asus Maximus VIII Hero to an Asus Strix Z490-F Gaming.
I had 4 Case fan connectors in the old Mb and now i have 2..
According to the specs, these are the connectors in the new Mobo:
1 x 4-Pin CPU Fan header
1 x 4-Pin CPU OPT Fan header
1 x 4-Pin AIO Pump header
2 x 4-Pin Chassis Fan headers
1 x 4-Pin M.2 Fan header
1 x W_PUMP+ header
1 x VRM Heatsink Fan header

I got:
2x 140m Corsair ML Pros in the front
1x 120 Corsair ML Pro on the bottom of the case blowing at my Graphic Card
1x Cooler Master 120mm fan in the back that came with my Cooler Master CM 690III Case.
I also have an NZXT X52 on the Top with 2x 120mm Fans controlled by NZXT Software (connected to CPU Fan header).

Now I don't have enough mobo connectors for the fans.. So my (hopefully temporary) solution was to plug the 2 140mm fans in the Kraken while the bottom and back fans are connected to the Mobo.
Are any of the other connectors viable? I have a "Y" connector where I would connect both front fans to as I actually want them to spin at the same speed, but I would like them to be individually controlled from the NZXT radiator fans.

Or, as a last alternative, is there a decent controller where the speed would be controlled by software Like the Corsair Commander Pro? Preferably Asus with integration in Asus Software..
 

Ralston18

Titan
Moderator
Fair question.

I do not have (full disclosure) a direct answer for you.

However, going back a step or two: are you able to truly validate the need for all those fans? And/or have direct control of the speeds?

This:

"I actually want them [front fans] to spin at the same speed, but I would like them to be individually controlled from the NZXT radiator fans."

So what happens if the radiator fans decide, for what ever reason, to spin at different speeds?

Seems to be getting cumbersome and that is often a good warning sign that things may be spiraling out of control.

A physical "Y" connector has no way to know which way to send electrons to equalize speeds.

Take another look at the overall cooling requirements and related plans.

Never let form get in the way of function.

Just my thoughts on the matter.
 

Paperdoc

Glorious
Ambassador
I have two questions to get exact info.

  1. Are the three Corsair fans the ML120 Pro LED units with only ONE cable from them, or the ML120 PRO RGB with TWO cables from them? The LED models use a bit more power on the connection from the mobo fan header.
  2. Look closely at the REAR fan pre-mounted in the case. Does the connector on the end of its power cable have THREE holes, or FOUR? This impacts the method of fan control, and thus how it can be connected to the mobo.
Whatever the answers are I can give you a good solution using Splitters, a Hub or one of each. Just some general notes so you understand what is possible.

When you connect two or more fans to a single header, all the fans receive the same speed control signals (either Voltage or PWM). If the fans are different models (you have three types) they will NOT operate at the same speed. Even if they are identical (you do have one matched pair), those two will differ very slightly in speed. None of this is a problem. The mobo does not actually try to control speed, and does not use the actual speed for its work. What it does is manipulate the signal to the fans (Voltage or PWM) to get them to blow enough air to keep the TEMPERATURE of a sensor on the mobo on target. The speed is not the target.

Any mobo fan header can deal with the speed signal sent back to it from ONE fan only. So any Splitter or Hub will send back only one of its fans' speeds and ignore all the others. You will never "see" those latter speeds anywhere. This has no impact on ability to control speeds. But it does impact the second header function, which is to monitor the speed signal for fan FAILURE. It cannot monitor a speed signal it does not get. So from time to time, YOU should check all the fans to be sure they are still working.

The method of controlling fan speed (that is, the details of the signal sent to it) is different between the older 3-pin fans and the newer 4-pin PWM fans. So generally they cannot be mixed on the same circuit. All your Corsair fans are 4-pin. We don't know yet about the rear pre-mounted fan, which is why I asked item 2 above.

You have one fan aimed at the GPU to ensure it gets lots of cooling air, and that is a good idea. You should understand that the speed of that fan can be controlled according to the mobo temperature sensor, which is reasonable. However, it can not be controlled by the actual temperature of the GPU chip on your graphics card - there is no way for the fan control system to access that info.

The two fans on the X52 AIO system rad are controlled according to a different temperature sensor inside the CPU chip, and that is done by the NZXT CAM software. It communicates with the pump unit of that system via the cable from the pump to a mobo USB2 header. This is not the ideal way to control the two front case fans, but it is OK for now until you get a better arrangement. By the way, with this system, the speed that the CPU_FAN header can read and tell you is NOT the CPU Fan speed - there is none. It is the PUMP speed, and it should always be full speed, typically over 2000. The CAM software tool can tell you that and label it properly. It also can tell the the rad fan speeds. So power and control of the pump and the two rad fans is NOT part of the considerations for CASE fan control.
 
Reactions: Ralston18

chegalhavara

Reputable
May 7, 2016
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First of all, thank you for the answers.

I think I didn't explain myself enough or correctly.
Extra information: I actually replaced my back fan for a Thermal Take 120(pwm) that I had laying around.

To answer both your questions: I do know how pwm fans work and also how fan hubs work. All my fans are PWM/4pin
My Kraken actually works as a hub, only recognizing the signal from first fan an applying the signal to all fans.
That means that if, for example, I have defined it to spin the fans at 50% speed, all the fans will spin (aproximatelly) at their individual 50% speed.
In my case that is actually not a big issue as both my 2 front ML 140 (Pro RED, not RGB) and the NZXT Aer 120P on the radiator have a max speed of about 2000rpm and the MLs move quite a bit more air thus maintaining a positive pressure inside the case (My main objective as well as cooling). Not only because the ML140s are pulling more air from the (mesh) front of the case than the AERs are able to push, but also because the Aer 120 are pushing air though the radiator that causes more resistance than the mesh in the front.
Btw I also checked the power required for all the fans: 0.28A for the MLs and 0.32A for the AERs. Not an issue for the Kraken (Sata powered)

And thank you for the info anyway (could be the case that I did not know) but I also know that the CPU FAN speed connector is not reporting the radiator fan speeds, but the pump speed.
Fan speed in the Kraken are (unfortunately) controlled by CAM (crappy) software.

The bottom ML120's speed is actually being controlled not by cpu temp, but through a sensor that I inserted between the GPU PCB and the backplate, so close to the GPU chip as I could.
The temps reported by the sensor are actually quite near to the GPU reportings. For example comparing the sensor temperature with the gpu temperature reported in HWInfo I got like a 2-3 degree (Celsius) difference. But my main objective for the bottom fan is to increase speed according to increase in GPU temp. And that is not actually my question.

As it is now, I got 2 fan connectors on the mobo Ch_Fan1 and Ch_Fan2: 1 for the back fan, 1 for the bottom ML120.
The 2 Aer 120s and the 2 ML140s are all connected to the kraken hub.

As i said in the main post, I have several fan connectors on my Mobo. I am asking if they are viable to connect my front fans. I would like to be able to increase speed in the front fans independently from the Kraken fans.
In the Asus Software one can define the fan speeds according to a max of 4 different sources. Meaning I could also increase the fan speeds, not only when cpu temp rises, but also when gpu temp rises.
And that is why I would like to connect the fans to the mobo. And I am asking if any of the other connectors are viable/usable/advisable to connect case fans to.
If that does not work, the only option would be to buy a Fan controller as the Corsair Commander.

So the questions are:
Are the other Mobo connectors viable/usable/advisable to connect case fans, in this case my 2 ML140 in the front?
If not, are there any advisable options apart from Corsair Commander? A Fan controller that is software controlled?

Thanks in advance
 
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