Pc cooling question. Which is better 3 120mm fans or 2 140mm fans

[Shyguy873]

Hello, I have a question that I want to know. Which is better when it comes to cooling, 3 120mm fans or 2 140mm fans? On the website for the case I have one of the sides support up to either 3 120’s or 2 140’s (the case I have is the MSI MPG Velox 100R if that info is useful) the fans I am planning on using is the Noctua A12x25 fan as my 120mm fans and the Noctua A14 fans as my 140mm fans if that is of any help. What is better at cooling the 3 A12x25’s or 2 A14’s?

 

[Dedayog]

27 minutes ago, Shyguy873 said:

Hello, I have a question that I want to know. Which is better when it comes to cooling, 3 120mm fans or 2 140mm fans? On the website for the case I have one of the sides support up to either 3 120’s or 2 140’s (the case I have is the MSI MPG Velox 100R if that info is useful) the fans I am planning on using is the Noctua A12x25 fan as my 120mm fans and the Noctua A14 fans as my 140mm fans if that is of any help. What is better at cooling the 3 A12x25’s or 2 A14’s?

 

What is the CFM of each fan?  Then math it.

 

From a fan radius calc, they're similar.  The 3x12 slightly better.  But also the 360mm AIO provides more radiator space to cool the water a little better, which nets 360 AIO's a bit stronger in cooling overall.

[Shyguy873]

Just now, Dedayog said:

What is the CFM of each fan?  Then math it.

 

From a fan radius calc, they're similar.  The 3x12 slightly better.  But also the 360mm AIO provides more radiator space to cool the water a little better, which nets 360 AIO's a bit stronger in cooling overall.

Is it linear? Like the airflow of 3 120’s is just the airflow of one 120 times 3?

[PDifolco]

3x120 are a tad better, they're smaller but spin faster and offer more air moving surface overall

But the case is so choked of air on the front that I suspect neither confuguration will be very useful...

[Shyguy873]

2 minutes ago, PDifolco said:

3x120 are a tad better, they're smaller but spin faster and offer more air moving surface overall

But the case is so choked of air on the front that I suspect neither confuguration will be very useful...

What do you mean by that part at the end?

[Zando_]

In this comparison the 120s are better. Noctua's NF-A12x25s are their best fan, they have not been able to beat it thus why there is no 140mm variant. The A14 is an older design. Both are fine (I use A14s) but the NF-A12x25 is a better balance of airflow/pressure vs noise. 

[brob]

42 minutes ago, Shyguy873 said:

Hello, I have a question that I want to know. Which is better when it comes to cooling, 3 120mm fans or 2 140mm fans? On the website for the case I have one of the sides support up to either 3 120’s or 2 140’s (the case I have is the MSI MPG Velox 100R if that info is useful) the fans I am planning on using is the Noctua A12x25 fan as my 120mm fans and the Noctua A14 fans as my 140mm fans if that is of any help. What is better at cooling the 3 A12x25’s or 2 A14’s?

 

 

Airflow through a case is what ultimately determines cooling. Just looking at one set of fans is usually insufficient for determining the optimal configuration.

 

[Middcore]

39 minutes ago, Shyguy873 said:

What do you mean by that part at the end?

The amount of air fans can move is irrelevant if no air can get into the case.

[PDifolco]

2 hours ago, Middcore said:

The amount of air fans can move is irrelevant if no air can get into the case.

Yep, this, case front has a big glass panel and only few side perforation, so air won't enter & flow much

[Shyguy873]

15 hours ago, PDifolco said:

Yep, this, case front has a big glass panel and only few side perforation, so air won't enter & flow much

Sadly I already have the case and I wasn’t the one who chose that case. It was a gift I got TuT so for a case like that with poor airflow is airflow of fans more important or is it static pressure?

[PDifolco]

1 minute ago, Shyguy873 said:

Sadly I already have the case and I wasn’t the one who chose that case. It was a gift I got TuT so for a case like that with poor airflow is airflow of fans more important or is it static pressure?

For  case fans it's airflow that matters the most, static pressure is mostly for rad fans

[Shyguy873]

27 minutes ago, PDifolco said:

For  case fans it's airflow that matters the most, static pressure is mostly for rad fans

so then is the only reason that 420 aios and rads are better then 360 only because the radiator being bigger? cause 420 rads use 140mm fan which have lower static pressure then 120mm fans. so the only reason 420 is a bit better then 360 because radiator size and not fans? 

[PDifolco]

9 minutes ago, Shyguy873 said:

so then is the only reason that 420 aios and rads are better then 360 only because the radiator being bigger? cause 420 rads use 140mm fan which have lower static pressure then 120mm fans. so the only reason 420 is a bit better then 360 because radiator size and not fans? 

140 mm fans don't have lower pressure than 120s, depends on fans

For  example Arctic P12s are rated at 2.2 H2O while P14s are rated 2.4

What can happend is that 120mm often have quite faster max speed,  with more pressure then, but they're annoyingly noisy at those speeds

Anyway indeed more rad surface also help temp, and overall 420s aren't that much better than 360

 

[brob]

16 minutes ago, Shyguy873 said:

so then is the only reason that 420 aios and rads are better then 360 only because the radiator being bigger? cause 420 rads use 140mm fan which have lower static pressure then 120mm fans. so the only reason 420 is a bit better then 360 because radiator size and not fans? 

 

I don't think the generalization is valid. In fact as @PDifolco points out it is an invalid assertion when it comes to Liquid Freezer AIO.

 

420 AIO generally offer more cooling surface which means its fans can usually spin at lower RPM to achieve the same cooling as a 360 model. Even that is a tenuous assertion as radiator surface area varies.

 

[PDifolco]

5 minutes ago, brob said:

 

I don't think the generalization is valid. In fact as @PDifolco points out it is an invalid assertion when it comes to Liquid Freezer AIO.

 

420 AIO generally offer more cooling surface which means its fans can usually spin at lower RPM to achieve the same cooling as a 360 model. Even that is a tenuous assertion as radiator surface area varies.

 

Yup as the "cooling surface" is the one of all the fins, depending on fin density, pattern,  and rad width as well...

[Shyguy873]

1 minute ago, PDifolco said:

Yup as the "cooling surface" is the one of all the fins, depending on fin density, pattern,  and rad width as well...

sorry, i dumb TuT