[SOLVED] Number of fans to complement NZXT Kraken Z73 360 mm

[tirantloblanc]

Hello, I need some advice on the optimal number of fans. This is my first time building with liquid cooling, and I am confused on how I should treat the radiator fans to ensure air INFLOW = air OUTFLOW.

I am planning a build with the following parts. Everything but the extra fans is already here or on the way.

Case: Corsair 5000D Airflow
CPU: i7 12700K
CPU Cooling: NZXT Kraken Liquid Cooler Z73 360 mm
GPU: ASUS ROG Strix GeForce RTX 3080 OC GAMING 10GB
Board: MSI MPG Z690 FORCE
RAM: Corsair Dominator 32GB DDR5 5600Mhz
PSU: Corsair RM1000x

The NZXT will likely be at the top, on exhaust mode.

I am planning to add Noctua NF-S12A PWM Case Fan 120 mm fans.

QUESTION 1: How many of these Noctuas do I need and where should they be? Should it be 3 in the front providing inflow, will that be equally matched by the three NZXT fans in the radiator? Or should I optimally also add an exhaust fan at the back?

QUESTION 2: If after testing I am not happy with the temperatures with 3 Noctuas intake, 3 NZXT radiator outflow, would adding an exhaust fan at the back and one intake on the side (the case allows up to 3 120mm on the side) help?

And finally, if I shouldn't do an extra exhaust fan at the back, what do people do in that situation to avoid dust getting in through the open mesh? Do I have to consider fashioning out my own filter fit to size?

Thanks!

 

[Phaaze88]

1)1 at the rear exhaust, the other 2 at the top exhaust. Of course that would mean the Kraken goes at the front, instead of where originally intended.
NF-S12As, which are optimal for use as case exhaust fans, less so as intakes because they lack static pressure to deal with obstacles.
Return the S12As and get two NF-A14s for front intake if you don't want to install the cooler at the front.

2)Help what? You need to be more specific here.

3)There's aftermarket 120mm fan filters out there for that, so no, you don't have to DIY your own filter.

 

[Nephern]

i suggest the front and side be filled up with 3 fans each

if you plan to put your radiator in one of those front spots, put it INWARD facing, as this makes it easier to clean, you shouldnt be able to see the fans on the radiator, it seems not fancy but when it comes time to clean out that radiator youll wish you had put it radiator facing in.

and in the top you can leave it open but if you want to put fans in there make them exhaust, you want an exhaust in the back no matter what.

i would also change the stock fans out of your nzxt fans for noctua fans, this brings your total to 9 fans (including top), the stock fans are not well built and are really put in there to save money and so they can meet bare minimum requirements.

The 5000d should hold up to 10 fans

so heres the layout.

Front: 3 intake (you should see the fan structure from inside of the case) 120mm

Side: 3 intake 120mm (RADIATOR)

Top: 2 exhaust 140mm

Back 1 exhaust 120mm

 

[tirantloblanc]

1)1 at the rear exhaust, the other 2 at the top exhaust. Of course that would mean the Kraken goes at the front, instead of where originally intended.
NF-S12As, which are optimal for use as case exhaust fans, less so as intakes because they lack static pressure to deal with obstacles.
Return the S12As and get two NF-A14s for front intake if you don't want to install the cooler at the front.

2)Help what? You need to be more specific here.

3)There's aftermarket 120mm fan filters out there for that, so no, you don't have to DIY your own filter.

Thank you. You make a very good point on the S12As not being so suitable as intake. I see the Noctua NF-A12x25 PWM are good all-arounders.

Based on this and more reading I am thinking of doing:

3 Noctua NF-A12x25 PWM in front - intake
2 Noctua NF-A12x25 PWM on side - intake
360 mm Kraken at the top - exhaust
1 Noctua NF-A12x25 PWM at the back - exhaust

That should be 5 intakes, 4 exhaust, which should keep the insides dust free and with good airflow. Anything wrong with this plan?

 

[Phaaze88]

Based on this and more reading I am thinking of doing:

3 Noctua NF-A12x25 PWM in front - intake
2 Noctua NF-A12x25 PWM on side - intake
360 mm Kraken at the top - exhaust
1 Noctua NF-A12x25 PWM at the back - exhaust

That should be 5 intakes, 4 exhaust, which should keep the insides dust free and with good airflow. Anything wrong with this plan?

Yeah, that's prioritizing airBLOW and aesthetics over airFLOW. Dust is inevitable as well, unless the room is vacuum sealed.
Just because a case has numerous optional fan options, doesn't mean it's necessary to fill every single space. There is a point of diminishing returns, typically at 4-6 fans for ATX-sized cases.
The more straightforward the airflow is, the more efficient cooling will be. Having the side in use just screws with that. Use it when intending to do a custom loop.

 

[tirantloblanc]

Yeah, that's prioritizing airBLOW and aesthetics over airFLOW. Dust is inevitable as well, unless the room is vacuum sealed.
Just because a case has numerous optional fan options, doesn't mean it's necessary to fill every single space. There is a point of diminishing returns, typically at 4-6 fans for ATX-sized cases.
The more straightforward the airflow is, the more efficient cooling will be. Having the side in use just screws with that. Use it when intending to do a custom loop.

Understood. My issue is that if I do want to keep the radiator on top, that's 3 fans exhaust + 1 fan in the back (which appears to be a very good idea almost always), that's 4 fans exhaust. So if in front I have just 3 fans, that's an imbalance that apparently is not advised, most say Intake fans should be equal to or higher than exhaust fans.

 

[tirantloblanc]

I guess the correct answer is radiator in front as intake and 1 exhaust fan on top 1 at the back? That's 3 and 2... That should technically be better airflow?

 

[Phaaze88]

Understood. My issue is that if I do want to keep the radiator on top, that's 3 fans exhaust + 1 fan in the back (which appears to be a very good idea almost always), that's 4 fans exhaust. So if in front I have just 3 fans, that's an imbalance that apparently is not advised, most say Intake fans should be equal to or higher than exhaust fans.

With air set up to enter from the front, with a bit of a curve upwards out the top and rear... the flow isn't going to get anymore straightforward than that.

That latter part is technically wrong, as the number of fans here and there don't decide what this 'balance/imbalance' is. It's not that simple.
-the fans(Kraken, Noctua, gpu) have different specs, and their performance does not scale linearly; what one fan does at a given speed, the other fans will not yield the same performance.
-personal fan curves tuned for your comfort level are there to throw in another wrench.
-case design... wrench again.
-fan & radiator positioning.
-the variable degrees of air restriction presented by obstacles such as filters, the style of the grilles, radiators, psu shrouds, HDD cages, etc...
-it's not like that case is vacuum sealed; there are places for air to drift in/out.

You have to do your own testing and comparisons if you want to get to the truth. All myself and others can do is speculate, which will ultimately get nowhere.

I guess the correct answer is radiator in front as intake and 1 exhaust fan on top 1 at the back? That's 3 and 2... That should technically be better airflow?

As long as you do one or the other:
A)Front fan intake, rear and top radiator exhaust
B)Front radiator intake, rear and top fan exhaust
It will be fine. They're both 'correct', and have their own little quirks.