2 80mm fan or 1 120 mm fan?

[whatever]

Hi all,


Which is better: two 80 mm fans or one 120 mm fan?

I'm considering getting a bigger pc case. One comes with one 120mm fan
on the rear and the other one with 2 80mm fans. Which config is better
in terms of cooling and noise?

Any advice on how to pick cooling fans (case fan) will be appreciated.

Thanks in advance.


JohnS

 

[w_tom]

You answer is found in the numbers for those fans. Many
80mm and 120 mm fans have different CFM and dB numbers.
Generally a 120 mm fan will move same air (CFM) with less
noise (dB). But first you must have numbers for those fans.
There both 80 and 120 mm fans with different numbers. Some 80
mm fans will move same air at higher noise levels.

 

[DaveW]

The single 120mm fan will be much quieter and will cool just as well as two
80 mm.

 

[Matt]

Any advice on how to pick cooling fans (case fan) will be appreciated.

The following should help people understand noise ratings.

Each increase of 10 dB represents multiplication of noise by a factor of
10. For example, a 40 dB noise source is 100 times as noisy as a 20 dB
noise source.

An increase of 3 dB represents approximately a doubling of noise. So
two 21 dB fans would make about as much noise as one 24 dB fan. Four 21
dB fans would make about as much noise as one 27 dB fan.

 

[Ruel Smith]

Hi all,


Which is better: two 80 mm fans or one 120 mm fan?

I'm considering getting a bigger pc case. One comes with one 120mm fan
on the rear and the other one with 2 80mm fans. Which config is better
in terms of cooling and noise?

Any advice on how to pick cooling fans (case fan) will be appreciated.

Thanks in advance.

You need to check the cfm that the fan moves and the noise level. I use
Antec fans because I have no trouble installing them in my Antec cases,
which are my favorites, and they're reliable. Check out their chart on the
air they move and thee dB of the sound they produce.

http://www.antec.com/pdf/Fan_Comparison_table.pdf

According to this chart, an 80mm LED fan moves 34 cfm or air @ 30 dB of
noise. It spins at 2600 rpm. Now, the 120mm LED fan moves 56 cfm of air @
28 dB and spins at 1600 rpm. Now, someone pointed out in another post that
you'll get an increase of about 3 dB for doubling the fans. Now, that would
mean a noise level of 33 dB for about 68 cfm of airflow. I say about,
because in real world situations, I don't think the airflow will be quite
so good as to be doubled. In contrast, you have 28 dB of noise and acheive
a 56 cfm of airflow. Now, this is where you need to make a decision: Is
cooling effectiveness more important, or the quietness of the PC?

Understand. I use only one brand to base this comparison on. If you use a
different brand, you need to check their specs and decide for yourself.

Personally, I like my system running as cool as possible. I run 5 80mm Antec
fans in one of my systems, and it's not annoying at all. Some people would
disagree.