Question Case airflow optimization

Jan 4, 2021
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Hey guys! I have recently built my very first desktop PC. I have a few questions about how to optimize the airflow while keeping my system relatively cool and maintaing decent performance.
I have SilentiumPC Armis AR6X TG RGB case with fans that the manufacturer gives with it and Gigabyte Z390 Gaming X motherboard. I already have a problem with bundled fan controller. I want to use something called Auto Fan Stop feature. It basically cuts off the power from a single PWM header when a temperature read by the chosen sensor gets below a given threshold. The issue is: the fan hub also performs RGB led control for up to 6 devices and PWM control for up to 6 fans. Therefore, it needs more power, which it draws from the PSU via SATA connector. When it detects no power from the PWM control socket, it just runs all the fans at their full speed, which is kind of contrary to what I want to achieve. I figured out that I am going to need fan splitters to make use of the fan stop feature. This is not a problem, but when I looked deeper at the airflow optimization issue, more questions arose. I am kindly asking them in this post, because I failed to find a comprehensive guide about this problem, so this post probably may become it if you wish to help!
  • My case has the following fans:
    • 3x 120 mm 0.2 amp on the front
    • 1x 120 mm 0.2 amp on the back
    • 1x 120 mm 0.12 amp on the top
And they all are DC, though the hub uses PWM for control. https://drive.google.com/file/d/1vV4C71ZpTz0BIUThsijaJniiMwDZLR_G/view?usp=sharing - this picture shows their layout.
The mainboard has 3 4-pin connectors plus CPU fan header.
  • I can't find any information about max power draw per one header for my mobo anywhere. Can I safely assume that less than 1 amp of 12V should be fine?
  • How should I configure the fan speed-to-temp curves? My mainboard has sensors on CPU, GPU, VRM, 1st BIOS core, 2nd BIOS core and on the south bridge. Generally speaking, I see higher temps on mosfet and south bridge, which, to the best of my knowledge, is normal. What sensors should I use for each fan? Should the front fans base their speeds on GPU temperature, or maybe CPU or voltage regulator? What about other fans? Right now while PC is idle (around 3% of computing power used by background processes and the processor running at around 2 GHz), the CPU gets to abour 35-38 degrees (with fan starting to spin at 40 degrees for about 3-4 seconds and stopping after temp falls below that point), VRM about 43 degrees, PCIE about 41 degrees, BIOS cores about 35-36, PCH 40 degrees. Under 100% load (stress test, small data set, steady load), CPU tops at about 77 degrees. Temps reported by the mainboard sensor are 10-11 degrees lower. VRM temps top at 66 degrees (by mainboard's sensor). Basically, when I torture my CPU, it stabilizes at about 1200 RPM fan speed and 69 (nice) degrees, with supporting fans on the back and top of the case spinning at 1200 and 1000 RPM respectively. When the load disappears, the fans stop after literally one second, which is cool. GPU temperature tops at 75 degrees, with fan spinning at 1500 RPM max. It has a hefty overclock - it's a GTX 1080 running at 1987 MHz, so bumped up by 254 MHz.
  • What temperatures are perfectly fine for different components? Since I want a perfectly silent PC while under no to small load, I want to turn off all the 7 fans I have in here while temps are below given points. What are the perfectly-fine-safe-af spots? Can I let my CPU fan rest when the processor is under 40, 45, 50 degrees? What about other components? Or maybe should I make the CPU fan spin all the time? My cooler is the Cooler Master Hyper 212 LED (though I have covered those irritating red LEDs with tape, even before I have started building I knew they were going to destroy my PC's easthetics).
I didn't even notice that I have created such a lengthy post, if no one reads it I would consider it totally understandable. So, how does it work? Is it someting like "make your PC as silent as possible just do not exceed temps x, y, z for components a, b, c", or maybe "it should stay below this temperatures, but on load it may get to those", or maybe something different? To the best of my knowledge, my idle temps look fine to leave the fans unspinning, but my knowledge is limited. I also have all three front fans spinning, had it not been for their work, the temps may be looking worse.
Thank you in advance for all your help. Also, I am not a native speaker, so if I have made some errors in this essay-esque post, forgive me!
 

Lutfij

Titan
Moderator
Welcome to the forums, newcomer!

As far as I know you can get up to 3 fans per header of the motherboard. Though please take this with a grain of salt since the advent of RGB and higher amperage fans, I'm referring to fans made a few years ago, so non-RGB fans.

I would suggest that you look into a PWM fan hub that relies on a PWM fan header not a 3pin connection/connector. Also, if you're interested in fan stop, how do you intend to have the RGB powered? Are the fans powered by an individual lead to the fans for RGB?

It's silly how the case doesn't have an e-manual on their support site.
 
Jan 4, 2021
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Thank you for such a quick answer @Lutfij ! Each of the RGB fans has two cables - one is a 3-pin DC used to control the fan itself, draws 12V 0.2 amps, and the second one is 4-pin RGB control drawing 0.3 amps on 12V. The RGB is powered from the PSU via an individual controller, so it is not an issue. All the power I need from a single header is 12V 0.2 amps times 3, so about 7.2 watts.
 

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