CaptainCanoy

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Nov 4, 2020
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So I have a Motherboard that is an ASRock X470 Gaming K4.
The problem is I want to put 6 (4 Pin Header) Case Fans in just 2 (4 pin) Chassis Fan Headers so I'm gonna split it into two.
The power of a single Case Fan of mine can consume 0.32 Ampere so if I multiply that into 3 it will be just 0.96 Ampere of most that they can consume.
And the Motherboards Power of the Chassis Fan Header is 2 Amperes. So I have more than enough to use 1 Header with 3 fans.

Question:

Is it really dangerous to put 3 Fans in just 1 header even though it's a 2 Amperes Chassis Fan Header? Is it gonna blow the motherboard and burn it?
 
Solution
As long as you actually have 2A fan headers you'll be fine. Most motherboards are restricted to 1A on most fan headers, anything greater will be an AIO or Pump header. So a broad statement of All the fan headers are 2A rated may or may not necessarily be true, only certain headers might. You will need to check with the motherboard manual specifically, and make sure per header.

Also to consider there is a margin of error. Nominally the fans will pull 0.32A at most, but some fans will spin upto 10% higher than rated, and possibly pull 10% or more as a result. So the fan might say 0.32A max, but in reality pull as much as 0.4A once it gets a little dirty.

That margin of error works both ways. Fan headers supposedly rated at 1.0A can be...

punkncat

Polypheme
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Arctic (for instance) recommends only using (3) of their fans together on the same header. I see that you have already considered the "math" of power draw. I don't think you will have issue in this case.
If it became concerning or have a need (or spot) for more fans, just get a hub.
 

CaptainCanoy

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Nov 4, 2020
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Arctic (for instance) recommends only using (3) of their fans together on the same header. I see that you have already considered the "math" of power draw. I don't think you will have issue in this case.
If it became concerning or have a need (or spot) for more fans, just get a hub.
I only plan to get a 3 in 1 (4 Pin) Cable and I just want to make sure that the Motherboard doesn't blow up on me so I asked in this community.
Getting a Hub is pricier than just a 3 in 1 Cable and the Power Draw doesn't exceed too much on it so no need for a hub. Just want to make sure that anything doesn't get wrong if I continued on that plan.
 

Karadjgne

Titan
Ambassador
As long as you actually have 2A fan headers you'll be fine. Most motherboards are restricted to 1A on most fan headers, anything greater will be an AIO or Pump header. So a broad statement of All the fan headers are 2A rated may or may not necessarily be true, only certain headers might. You will need to check with the motherboard manual specifically, and make sure per header.

Also to consider there is a margin of error. Nominally the fans will pull 0.32A at most, but some fans will spin upto 10% higher than rated, and possibly pull 10% or more as a result. So the fan might say 0.32A max, but in reality pull as much as 0.4A once it gets a little dirty.

That margin of error works both ways. Fan headers supposedly rated at 1.0A can be problematic at anything over 0.8A continuous. If you are unlucky enough, you'll get a header realistically rated at 0.8A, and 2x fans that pull closer to 0.4A, meaning you shouldn't then add a third fan on the splitter.

Generally 66% is my max for any fan header, since I can't test individual fans for actual power draw or headers for maximum real draw, so if your header of choice is actually just 1.0A and not a 2.0A header, I'd just run 2x fans from it.

Or, take the safe route, use a 4way powered splitter, which has zero draw from the header no matter how many fans used, it only uses the pwm signal from the primary split.
 
Solution