[SOLVED] Question about Fan control and Fan hub(s).

[AristosT]

Hello! I want to improve my airflow in my PC and I want to be able to control it.

My PC build is:
CPU: i9-10900 (non-K)
CPU COOLER: NOCTUA NH-D15 (with 2 Noctua fans that it came with)
GPU: MSI 3090 GAMING X TRIO
RAM : 2 x 16GB CORSAIR VENGEANCE 3200MHZ
MOTHERBOARD: ASROCK Z490 TAICHI
PC CASE: PHANTEKS P600S
PSU: CORSAIR HX1200
STORAGE: 1 x CORSAIR MP510 1TB, 1 x ADATA SX8200 2TB
OS: WINDOWS 10 PRO 64BIT

I currently have 3 x NoctuaNF-A15 HS-PWM 140mm in the front of the case as intake, 1 x Noctua NF-A15 HS-PWM 140mm in the rear as exhaust and 1 x Noctua NF-A15 HS-PWM 140mm in the top as exhaust. I want to add another Noctua NF-A15 HS-PWM 140mm in the top for exhaust as well, that would improve my overall airflow, correct? Also, I am looking to be able to control all the 6 x Noctua NF-A15 HS-PWM 140mm, the 3 in the front and 3 in the back, and I don't know how to do that. I was thinking of adding 2 x Noctua NA-FC1, 1 for the 3 fans in the front and 1 for the 1 fan in the rear and 2 at the top. My question is, can I control the fans RPM, individually, or as a group of 3 ( 3 intake front, 1 rear and 2 top exhaust)? Also, in case I need one or more extension cables, could I connect one extension cable to the Noctua NA-FC1, then connect the 3-way splitter to the extension cable then and then the fans to the 3 seperate headers of the splitter? Last, if I'm to get 2 x Noctua NA-FC1, where should I connect them on my motherboard? Is there a better fan hub I can plug and connect all of my fans to?

I'm really lost, any help would be greatly appreciated, thanks in advance!

 

[Paperdoc]

It will probably improve your overall air flow a modest amount. That would give you three intake fans and three exhaust, all the same model. Because the intake fans' air flow is slightly reduced by the dust filters in front of them, the new flow balance would be slightly more exhaust flow capacity than intake, leading to a small negative pressure inside your case. Personally, I prefer to have it slightly positive, but that's a different discussion.

I say modest improvement because you may NOT observe what I suspect you are looking for. I bet you are expecting this change to reduce some temperature reading in your system - maybe the CPU Temp, or the System Temp. However, for each of those, the default automatic fan control system alters its respective fan speed (either the ones on your CPU cooler, or the ones for the case) to whatever it takes to keep the actual measured temperature at a pre-defined target. In a system with good fans already like yours, that aim already is being met. The impact of adding one more fan to increase the total maximum capacity for air flow will be to allow that automatic system to slow down all of the fans slightly and continue to achieve the SAME measured temperature with a little less effort on the part of each fan. The only time such a change will make a significant impact on actual temperatures is when you operate at maximum workload causing all the fans to reach max speed to keep up with the heat - THEN the max temp might be lower with six fans than with five.

That said, I suggest you do not need those Noctua NA-FC1 units. They really are their own type of manually-adjustable fan controller, and they happen to come with a 3-output Splitter. If you connect one of those directly to a PSU SATA power output you can use its knob to set a speed manually. OR, if you connect it ALSO (using a cable provided) to a mobo header providing a PWM control signal, it will allow the mobo header signal to control the fan speed IF you turn the manual knob to max. If you turn the knob lower, it will just reduce whatever speed the mobo header requests to something lower. You could accomplish all of that just by using the mobo header's configuration settings without using the NA-FC1 unit at all.

The fans on your CPU cooler are connected to the CPU_FAN header, I presume. So you have six Noctua NF-A15 HS-PWM fans for case ventilation, and your mobo has six CHA_FANn / W_PUMP headers for that. You actually could connect each fan to its own header and configure all of them identically so they do exactly the same thing. The configuration to set for ALL of those headers would be (see your manual. p. 103-104):

CHA_FANn / W_PUMP Switch to Chassis Fan
Control Mode to PWM
Setting to Standard (see below)
Temp Source to the Motherboard sensor, not the one inside the CPU chip
Step Up and Step Down settings as default

Make those settings for each header separately, then use Esc back to Main Menu and F10 to get to Exit Menu (p.111). There choose Save Changes and Exit to save and reboot. This will use the pre-programmed speed-versus-temperature settings, guided by the temperature measured by the motherboard general sensor, to control all your case fans identically. Since each fan is connected to its own header, you will be able to "see" in BIOS Setup the speed of each fan. Also check the CD of utilities that came with your mobo for the Dragon Utility. It runs under Windows. I expect among many items it will have screens to show you the fan performance and temperatures under actual operating use, and allow you to adjust some parameters.

I advised above that you set the "Setting" item for each header to Standard as a start. After you get some experience how that goes, you can come back here and choose instead the Customize option. This allows you to change the speed to be used for each of several measured temperatures. So you could speed up or slow down all your fans and see what that accomplishes. If you wanted to slow down slightly all the exhaust fans to achieve a positive internal pressure, you could do that. Your mobo allows you lots of ability.

 

[AristosT]

It will probably improve your overall air flow a modest amount. That would give you three intake fans and three exhaust, all the same model. Because the intake fans' air flow is slightly reduced by the dust filters in front of them, the new flow balance would be slightly more exhaust flow capacity than intake, leading to a small negative pressure inside your case. Personally, I prefer to have it slightly positive, but that's a different discussion.

I say modest improvement because you may NOT observe what I suspect you are looking for. I bet you are expecting this change to reduce some temperature reading in your system - maybe the CPU Temp, or the System Temp. However, for each of those, the default automatic fan control system alters its respective fan speed (either the ones on your CPU cooler, or the ones for the case) to whatever it takes to keep the actual measured temperature at a pre-defined target. In a system with good fans already like yours, that aim already is being met. The impact of adding one more fan to increase the total maximum capacity for air flow will be to allow that automatic system to slow down all of the fans slightly and continue to achieve the SAME measured temperature with a little less effort on the part of each fan. The only time such a change will make a significant impact on actual temperatures is when you operate at maximum workload causing all the fans to reach max speed to keep up with the heat - THEN the max temp might be lower with six fans than with five.

That said, I suggest you do not need those Noctua NA-FC1 units. They really are their own type of manually-adjustable fan controller, and they happen to come with a 3-output Splitter. If you connect one of those directly to a PSU SATA power output you can use its knob to set a speed manually. OR, if you connect it ALSO (using a cable provided) to a mobo header providing a PWM control signal, it will allow the mobo header signal to control the fan speed IF you turn the manual knob to max. If you turn the knob lower, it will just reduce whatever speed the mobo header requests to something lower. You could accomplish all of that just by using the mobo header's configuration settings without using the NA-FC1 unit at all.

The fans on your CPU cooler are connected to the CPU_FAN header, I presume. So you have six Noctua NF-A15 HS-PWM fans for case ventilation, and your mobo has six CHA_FANn / W_PUMP headers for that. You actually could connect each fan to its own header and configure all of them identically so they do exactly the same thing. The configuration to set for ALL of those headers would be (see your manual. p. 103-104):

CHA_FANn / W_PUMP Switch to Chassis Fan
Control Mode to PWM
Setting to Standard (see below)
Temp Source to the Motherboard sensor, not the one inside the CPU chip
Step Up and Step Down settings as default

Make those settings for each header separately, then use Esc back to Main Menu and F10 to get to Exit Menu (p.111). There choose Save Changes and Exit to save and reboot. This will use the pre-programmed speed-versus-temperature settings, guided by the temperature measured by the motherboard general sensor, to control all your case fans identically. Since each fan is connected to its own header, you will be able to "see" in BIOS Setup the speed of each fan. Also check the CD of utilities that came with your mobo for the Dragon Utility. It runs under Windows. I expect among many items it will have screens to show you the fan performance and temperatures under actual operating use, and allow you to adjust some parameters.

I advised above that you set the "Setting" item for each header to Standard as a start. After you get some experience how that goes, you can come back here and choose instead the Customize option. This allows you to change the speed to be used for each of several measured temperatures. So you could speed up or slow down all your fans and see what that accomplishes. If you wanted to slow down slightly all the exhaust fans to achieve a positive internal pressure, you could do that. Your mobo allows you lots of ability.

Thank you for your detailed reply. So all in all, it's better and easier if I connect each of the fans to its own respective header, since my motherboard has 6 chassis fan headers and I have 6 fans, and that way I can see the RPM and control each one individually, correct? As for the settings, yes I will go with what you said, Motherboard sensor and Standard Mode, and work my way from there to see what suits me best. Also, since I will plug all of my fans to the motherboard headers, any fan hub is obsolete, right?

 

[Paperdoc]

Yes, you got that all correct.

 

[Paperdoc]

Thanks for Best Solution.

 

[AristosT]

Thanks for Best Solution.

Thank you very much, you have helped me alot.