Multiple case fans, 2 motherboard connectors

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jokerman54

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Hi, I'm building a new PC and the case comes with two front fans (called Fractal Design Silent Series LL 120mm). I want to install 2 more fans at the top (Corsair ML120 120mm PWM Premium) and one at the back (Cooler Master Silencio FP 120). The motherboard (Asus B350 Plus) has only two headers for case fans (plus one more for the CPU fan). Can I use PWM splitters to connect all of the fans? I thought of using one splitter for the front fans and 2 splitters for the top/back. Is it even possible that the motherboard controls the speed to all of them? I couldn't find any info about the Fractal Design fans.
What is the best possible setup for these fans since everything is already ordered. Maybe connect one or two of them (for example the front fans) directly to the PSU and use only one splitter?
I already have three Akasa PWM fan splitters and I could use everything if necessary.
Thanks in advance!
 
Solution
DRagor
Yes, you can use the setup you mentioned (2 front on one splitter, the rest on another). Yes motherboard will be able to control them, although of course all fans connected to one splitter will run at same speed (% speed, not RPM speed). Though it seems those Fractal Design fans are only 3-pin, so you will need to swap control mode for them to DC in motherboard BIOS.
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DRagor

DRagor

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Yes, you can use the setup you mentioned (2 front on one splitter, the rest on another). Yes motherboard will be able to control them, although of course all fans connected to one splitter will run at same speed (% speed, not RPM speed). Though it seems those Fractal Design fans are only 3-pin, so you will need to swap control mode for them to DC in motherboard BIOS.
 
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jokerman54

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I got 2 questions from what you said. If I connect the corsair fans together with the cooler master fan and then change to DC, will it not change for all of the fans since they are controlled from the same header? Btw the splitters split to 3pin in one end and 4pin in the other, so that you always see the RPM of just one fan.
Second question, the box of the cooler master says Safety current 0,5A. At corsair's website it says Power Draw 0.225A. All together it gets to 0,95A. I thought that the header gives just 1A. Is it safe to come so close to that number? Maybe my calculations are wrong because the cooler master also says Rated Current 0,05A.
 
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DRagor

DRagor

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Corsair fans and CM fan are all PWM, connect them to one splitter and keep the header at PWM. Fans that come with case should be connected to second splitter, and their header changed to DC IF they are 3-pin indeed, keep at PWM otherwise.
Cooler master fan at max is 0.16 A, so total is just 0.61 W, well below 1 A.
You are correct about splitter - motherboard sees only speed of the fan connected to the 4-pin header, but can't see speed of other fans on the splitter. However all fans on splitter get the same pulse modulation signal so they all go to same speed - again, percentile. Note that max speed of CM fan is 1400, while Corsair goes to 2400. So if you set up header to 100%, they will reach 1400/2400 respectively. If header is set to 50% speed, you will get 1100/1400. And so on.
 
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jokerman54

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Oh, sorry. I read wrong. I thought you said that I should change the corsair to DC. Now it makes sense! You seem also very certain that the cooler master is at max 0,16A! Thank you very much for your time and the answers!
 
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jokerman54

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Do you believe that I'm gonna get too much negative pressure with these exhaust fans compared to the front fans? should I maybe put the corsairs on the front and find a better setup with the splitters, for example Fractal Design on the top and one header, corsair in front and the other header and the cooler master directly to the PSU as it is a silent one at just 11dB and 1200 RPM (+/- 200) compared to all the others that are a little more noisy?
(This case with these fans was a last minute solution, originally I was going with another case that only head a rear fan, and I would put the Cooler master on the top and the corsairs on the front)
How would you install them if you had these and you had to choose?
Thanks in advance!
 
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DRagor

DRagor

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Like you mentioned, not too much info on those fans included with case, so hard to say. Negative pressure is not guaranteed, even with 3 exhaust vs 2 intake, if you don't know how much air those intake fans will move. Also you don't know if they are loud, and at what speed. So best thing to do is connect them and see what you got. If the setup is too loud, or seems to cool poorly, change it. Don't be afraid to experiment, as you have all the necessary parts at hand, it costs nothing save time.
One warning though - don't mix 3-pin and 4-pin fans on same splitter. If you set it to PWM, 3-pin fans will run full speed; if you set to DC, 4-pin fan may fail below certain voltage.
 
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