Question about push/pull configurations

[ancienttreedweller]

Hi All,

 

I'm planning to use two different fans in a push/pull config on a 120mm radiator. These are the specs:

 

'Push' fan:

static pressure: 3.08 mm/H2O.

air flow: 83.64 CFM

speed: 2200rpm

 

'Pull' fan:

static pressure: 3.10 mm/H2O

air flow: 63.74 CFM

speed: 2350 rpm

 

As you can see, they have slightly different specs. Both these fans will be running at full speed all the time. I've only ever seen people use identical fans for push/pull. Will this kind of setup cause any problems?

 

As a side note, I believe a push/pull config wont increase the airflow, but only increase the total static pressure on my radiator. Can someone confirm this? Thanks!

 

[79wjd]

Push/Pull won't improve anything if they're running at full speed. Part of the benefit of push/pull is slowing the fans down significantly. 

 

But no, there won't be any issues with using different fans. 

[ancienttreedweller]

1 minute ago, djdwosk97 said:

Push/Pull won't improve anything if they're running at full speed. Part of the benefit of push/pull is slowing the fans down significantly. 

 

But no, there won't be any issues with using different fans. 

 

If I run these fans at slower speeds, wont that reduce the airflow in terms of CFM?

[79wjd]

5 minutes ago, ancienttreedweller said:

 

If I run these fans at slower speeds, wont that reduce the airflow in terms of CFM?

That's the point of doing push/pull, to maintain a high enough flow of air without having to run the fans as fast. 

 

You have to realize that at some point you could make those fans spin faster and faster and it would literally make no difference on performance. Once you reach that point a higher flow of air won't improve temps. 

 

Take my Seidon 240m as an example, with the fans at 50% my cpu gets up to 70ºc, at 70% it gets to 65ºc and at 100% it gets to like 63ºc, at 200% in would probably be the same 63ºc~. 

[ancienttreedweller]

6 minutes ago, djdwosk97 said:

That's the point of doing push/pull, to maintain a high enough flow of air without having to run the fans as fast. 

 

You have to realize that at some point you could make those fans spin faster and faster and it would literally make no difference on performance. Once you reach that point a higher flow of air won't improve temps. 

 

Take my Seidon 240m as an example, with the fans at 50% my cpu gets up to 70ºc, at 70% it gets to 65ºc and at 100% it gets to like 63ºc, at 200% in would probably be the same 63ºc~. 

I see. So i'll have to experiment with different fan speeds and see what makes the most sense. 

 

 

[ancienttreedweller]

11 minutes ago, CUDA_Cores said:

yes it will reduce airflow, but to counter that you can simply add more fans. I am a silence freak and my computer has 8 fans in it. You may think that my computer is incredibly loud but it is not because none of those fans exceed 900RPM.

The reason i asked about airflow is that i want to make sure i have a slight positive pressure inside the case. So you're saying the best solution is to have the fans running as slow as possible while still having good cooling performance, and then add more fans elsewhere to to get the airflow right?

[79wjd]

4 minutes ago, ancienttreedweller said:

The reason i asked about airflow is that i want to make sure i have a slight positive pressure inside the case. So you're saying the best solution is to have the fans running as slow as possible while still having good cooling performance, and then add more fans elsewhere to to get the airflow right?

It's best to do whatever makes your ears happy. If you find the sound of a loud computer/fan soothing, then you should run them all at 100%. 

 

I personally don't want to hear my computer so I slow everything down to the point that I can no longer hear them, and then see how far I can overclock. 

[ancienttreedweller]

8 minutes ago, djdwosk97 said:

It's best to do whatever makes your ears happy. If you find the sound of a loud computer/fan soothing, then you should run them all at 100%. 

 

I personally don't want to hear my computer so I slow everything down to the point that I can no longer hear them, and then see how far I can overclock. 

Thanks a lot! I know what i need to do now. 

[ancienttreedweller]

8 minutes ago, CUDA_Cores said:

If you are a silence freak like me then yes, this is how you get your computer to be as quiet as possible. 

Thanks mate 

 

you guys are really helpful

[jasonvp]

1 hour ago, CUDA_Cores said:

You may think that my computer is incredibly loud but it is not because none of those fans exceed 900RPM.

Amateur.  Mine are down at 700RPM.  450RPM for the chassis fans. ;-)