My First Build: (Gigabyte X399 Aorus Xtreme) MotherBoard Header Amperage and PWM Fan Splitter Help

Dec 5, 2018
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Hey guys,

I am building a computer for the fastest possible 3D rendering, simulations, and machine learning/ai. Fast machine under heavy load means large amounts of heat, so I have already purchased a heap of EK Furious Vardar Evo 120mm fans (https://www.ekwb.com/shop/ek-furious-vardar-evo-120-bb-1200-3000rpm). I am going to be using these for water cooling, pushing air through 480 mm Hardware Labs Black Ice Nemesis GTR radiators (http://hardwarelabs.com/nemesis/gtr/gtr-480/), as well as regulating the air pressure in my case. According to my research (and ThermalBench.com), these are some of the best performance fans for cooling at the 3000 rpm range through a radiator.

PSA: I have chosen these fans specifically for their cooling ability, I do not care about the noise levels they produce.

The motherboard I chose to hold everything together is the Gigabyte x399 Aorus Extreme (https://www.newegg.com/Product/Product.aspx?Item=N82E16813145084). Their hybrid fan headers are rated for 2 amps and 24 volts. The EK Vardar fans I have purchased pull .47 amps per fan. I want to be able to use a fan splitter or fan hub to be able to plug 3 or 4 fans into a header on the motherboard. The PSU I have chosen is the EVGA SuperNova 1600 T2 Titanium (https://www.evga.com/products/product.aspx?pn=220-T2-1600-X1)

I have a few questions about these specs, as well as how some of these parts/equations work, considering I have seen multitudes of conflicting information online.

1. What exactly does "fan headers rated for 2 amps, up to 24 volts" mean? (information found here https://www.gigabyte.com/us/mb/aorus/cooling Smart Fan 5 tab)

I have seen some people say this means EACH fan header is capable of supporting 2 amps of draw on it. Others have said that the TOTAL draw on ALL fan headers cannot exceed 2 amps. Which is correct?


2. How do PWM fan hubs work, and can you ignore amperage pull from the fans if the PWM fan hub is connected to the PSU?

I want to be able to connect 3 or 4 fans to a single fan header with a fan hub or splitter. If I connect 3 of my fans, my fans will draw 1.41 amps, which is high, but nicely under the 2 amp limit. If I want to connect 4 however, I will be drawing 1.88 amps, which is a little too high for my comfort zone. I have seen on a few websites and heard from a few people that you can ignore the amp pull of the fans if one end of the PWM fan splitter/hub is connected to the PSU and the motherboard, while the others are connected to the fans. Is this correct? This splitter supports 5 fans and connects to a PWM header on the motherboard and a SATA connector for the PSU (http://www.akasa.com.tw/update.php?tpl=product/product.detail.tpl&no=181&type=Cables&type_sub=Fan%20Cable%20Adapters&model=AK-CBFA07-45). Would I be able to connect 5 fans to this, totaling a pull of 2.35 amps from the PSU? Theoretically, could I find an 8 fan splitter and draw 3.76 amps from the PSU? Or will this draw also affect the motherboard via the PWM header?

3. How do you calculate startup amperage?

Many sites talk about startup amperage on fans, that this amperage is higher than the amps most companies list for their fans, and that this can blow your fan headers if the rated amps are exceeded. As it says above, I want to be able to connect 3 or 4 fans to a single header. If I connect 4 fans with a total amp pull of 1.88, plus a startup amp increase per fan, it would blow my header correct? If I connect 3 fans with a pull of .47 amps each, I can only support an increase of .196 repeating amps maximum per before exceeding that 2 amp total limit. Is there a way for me to calculate the startup amperage of a fan so I can be sure to stay at/under my header amp limit?

Ok, those are my questions at the moment. Thanks in advance for the help! I have spent hours trying to find this information and can't seem to find anything definitive, so hopefully this will help others in the future!
 
Dec 5, 2018
4
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MERGED QUESTION
Question from gildedbacon : "Gigabyte X399 Aorus Xtreme MotherBoard and EK Furious Vardar Evo 120mm Amperage Help"

Hey guys,

I am building a computer for the fastest possible 3D rendering, simulations, and machine learning/ai. Fast machine under heavy load means large amounts of heat, so I have already purchased a heap of EK Furious Vardar Evo 120mm fans (https://www.ekwb.com/shop/ek-furious-vardar-evo-120-bb-...). I am going to be using these for water cooling, pushing air through 480 mm Hardware Labs Black Ice Nemesis GTR radiators (http://hardwarelabs.com/nemesis/gtr/gtr-480/), as well as regulating the air pressure in my case. According to my research (and ThermalBench.com), these are some of the best performance fans for cooling at the 3000 rpm range through a radiator.

PSA: I have chosen these fans specifically for their cooling ability, I do not care about the noise levels they produce.

The motherboard I chose to hold everything together is the Gigabyte x399 Aorus Extreme (https://www.newegg.com/Product/Product.aspx?Item=N82E16...). Their hybrid fan headers are rated for 2 amps and 24 volts. The EK Vardar fans I have purchased pull .47 amps per fan. I want to be able to use a fan splitter or fan hub to be able to plug 3 or 4 fans into a header on the motherboard. The PSU I have chosen is the EVGA SuperNova 1600 T2 Titanium (https://www.evga.com/products/product.aspx?pn=220-T2-16...)

I have a few questions about these specs, as well as how some of these parts/equations work, considering I have seen multitudes of conflicting information online.

1. What exactly does "fan headers rated for 2 amps, up to 24 volts" mean? (information found here https://www.gigabyte.com/us/mb/aorus/cooling Smart Fan 5 tab)

I have seen some people say this means EACH fan header is capable of supporting 2 amps of draw on it. Others have said that the TOTAL draw on ALL fan headers cannot exceed 2 amps. Which is correct?


2. How do PWM fan hubs work, and can you ignore amperage pull from the fans if the PWM fan hub is connected to the PSU?

I want to be able to connect 3 or 4 fans to a single fan header with a fan hub or splitter. If I connect 3 of my fans, my fans will draw 1.41 amps, which is high, but nicely under the 2 amp limit. If I want to connect 4 however, I will be drawing 1.88 amps, which is a little too high for my comfort zone. I have seen on a few websites and heard from a few people that you can ignore the amp pull of the fans if one end of the PWM fan splitter/hub is connected to the PSU and the motherboard, while the others are connected to the fans. Is this correct? This splitter supports 5 fans and connects to a PWM header on the motherboard and a SATA connector for the PSU (http://www.akasa.com.tw/update.php?tpl=product/product....). Would I be able to connect 5 fans to this, totaling a pull of 2.35 amps from the PSU? Theoretically, could I find an 8 fan splitter and draw 3.76 amps from the PSU? Or will this draw also affect the motherboard via the PWM header?

3. How do you calculate startup amperage?

Many sites talk about startup amperage on fans, that this amperage is higher than the amps most companies list for their fans, and that this can blow your fan headers if the rated amps are exceeded. As it says above, I want to be able to connect 3 or 4 fans to a single header. If I connect 4 fans with a total amp pull of 1.88, plus a startup amp increase per fan, it would blow my header correct? If I connect 3 fans with a pull of .47 amps each, I can only support an increase of .196 repeating amps maximum per before exceeding that 2 amp total limit. Is there a way for me to calculate the startup amperage of a fan so I can be sure to stay at/under my header amp limit?

Ok, those are my questions at the moment. Thanks in advance for the help! I have spent hours trying to find this information and can't seem to find anything definitive, so hopefully this will help others in the future!
 

Lutfij

Titan
Moderator
Please don't create multiple threads on the same topic.

Why don't you just pick up a PWM Fan hub like the ones Phanteks, Silverstone, Swiftech and Akasa make? You can add more to the externally and rely on the PWM fan header on your motherboard and not worry about amperage off one header. If you pick up the Phanteks PWM fan hub, with the right splitters you can have 12 fans off one hub.
 
Dec 5, 2018
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Ok, that sounds awesome! Let me know if I understand you correctly. Using a PWM fan hub, I am able to connect one cable to the Power Supply, the other cable to the PWM header to regulate power consumption, and my fans to the hub inputs. I will be able to connect as many fans as the hub allows, regardless of the amperage each fan pulls because while my hub is connected to the PSU, there will not be any amperage pulled from the PWM header on the motherboard.

Is this correct?

Also, I apologize for posting in two areas. I realized after posting the first time that I may have posted in the wrong catagory, but wasn't sure how to change it. I posted in motherboards, then tried to delete the older one, but couldn't find how to do that either.