Air Flow in PC CPU

[DeenzX]

Currently, I have a NZXT Phantom 410 casing
(Current rig: i7 - 2600
Asus MOBO
Leadtek GTX 580 2GB
Corsair 750W PSU
250GB Kingston SSD
1TB WD HDD)

and I have space for up to a total of 7 cooling fans, but I have 5 installed for now.
Below is the image showing the locations where I can mount cooling fans:
(Blue for intake, Red for output)

And,
below is the image showing where I have my 5 cooling fans currently installed:
(Blue for intake, Red for output, Green for intended airflow)

I would like to add 1 more at the bottom, but I realized that this will make 4 inputs and only 2 outputs. Will it affect the cross ventilation of my system? Especially since I aim to provide a constant supply of fresh air to my GPU and CPU as much as possible. Which are the best locations for inputs and outputs in your opinion? Please share.

 

[DeenzX]

Need some comments on this!

 

[teddy1994]

I take it that u have a ref gpu? Top rear intake will just suck the hot air back into the case, best to be exhaust

Front, bot and side intake, rear and top exhaust.

Having more air intake means positive pressure in the case which result in lesser dust in the case
Having more air exhaust means negative pressure in the case which result in more dust, but have better cooling effect.
I would suggest more intake as you dun really need lots of cooling if not oc-ing

 

[jtjt00]

As teddy1994 mention, this is likely the most optimum cooling. Adding more fan may not lead to significant temperature drop. On the other hand, additional fan sure leads to more noise and dust.

 

[chillisauce]

Not sure if using the rear exhaust as intake is a good idea, it seems that a lot of people are saying that negative pressure (more exhaust than intake) is the way to go. What are you using to cool your CPU? And are there any OC?

 

[gaoxing84]

Rear is always exhaust I feel. Get a airflow fan. Not static pressure. Static pressure for front to push air thru hdd cages, bottom also, all intake. Top can use airflow fan if not using rad to push air out of the case.

 

[DeenzX]

I take it that u have a ref gpu? Top rear intake will just suck the hot air back into the case, best to be exhaust

Front, bot and side intake, rear and top exhaust.

Having more air intake means positive pressure in the case which result in lesser dust in the case
Having more air exhaust means negative pressure in the case which result in more dust, but have better cooling effect.
I would suggest more intake as you dun really need lots of cooling if not oc-ing

Yes, it is a reference one. Also, I do agree the hot air expelled from the GPU will eventually by suck in from the fan behind. The problem I have now is if the back fan is an output, it will cause a negative pressure in my case, and thus more dust. The top 2 fans are not suitable for intake as it will attract more dust due to gravity pulling down everything.

 

[DeenzX]

As teddy1994 mention, this is likely the most optimum cooling. Adding more fan may not lead to significant temperature drop. On the other hand, additional fan sure leads to more noise and dust.

I have dust filters for those intakes. Noise? I don't think my fans are that powerful to make any noise

 

[DeenzX]

Rear is always exhaust I feel. Get a airflow fan. Not static pressure. Static pressure for front to push air thru hdd cages, bottom also, all intake. Top can use airflow fan if not using rad to push air out of the case.

Oh, learnt something new about static pressure fans. Cool, I'll allocate 2 pressure fans at the front 2.

 

[teddy1994]

Yes, it is a reference one. Also, I do agree the hot air expelled from the GPU will eventually by suck in from the fan behind. The problem I have now is if the back fan is an output, it will cause a negative pressure in my case, and thus more dust. The top 2 fans are not suitable for intake as it will attract more dust due to gravity pulling down everything.

Different fans have different airflow rate. For intake, just use higher performance fans, while for exhaust, can use lower performance fans

As long as intake cfm is more than exhaust, it is most likely positive pressure

Or if all fans are the same, can probably use low voltage cable or certain programs/bios or fan speed controls to slow down the exhaust fan

 

[Kince86]

Pardon me while i highjack your thread XD
Is it ok to have both intake and output on the top fans? Im thinking the rear-top AF fan exhaust and front-top SP fan intake.
And maybe partition them with a light plastic board between them if needed?

So this will be 4 SP intakes and 2 AF exhaust.

 

[DeenzX]

Pardon me while i highjack your thread XD
Is it ok to have both intake and output on the top fans? Im thinking the rear-top AF fan exhaust and front-top SP fan intake.
And maybe partition them with a light plastic board between them if needed?

So this will be 4 SP intakes and 2 AF exhaust.

Go ahead. This is a discussion anyways
I think that if you do that, the air will just go around and around those 2 fans. it is an endless cycle.

 

[DeenzX]

I am always very interested and amused at how something we cannot see (air) affects everything. I would very much like to physically see airflow but that is not possible without a medium such as dry ice. I have found a few videos displaying air flow in CPUs, and it is very interesting.

http://www.youtube.com/watch?v=wOMkW7YybWg
http://www.youtube.com/watch?v=BaZJ2cJS6tM
http://www.youtube.com/watch?v=goIqKrL3RGQ

 

[Shutterbox]

Good thread.

better bookmark before this get lost in threads of 'recommend me rig budget of 0.8k"

 

[Kince86]

Go ahead. This is a discussion anyways
I think that if you do that, the air will just go around and around those 2 fans. it is an endless cycle.

Yeah thats why i mentioned a plastic board to partition the 2 fans so the intake air gets directed downwards to be caught by the front fans and pushed to the back which then gets sucked out by the 2 exhaust
Looks might be affected tho

 

[geodudenest]

I am currently using : intakes (2 front, 1 side, 1 rear, 1 bottom) exhaust ( 2 top).
Cpu is air-cooled in pull with heatsink in vertical orientation, so that the heat from cpu is exhausted directly to top exhaust.
Honestly, there wont be much of a change in temps.

 

[EatSnakeWarrior]

I'm using a corsair 540

so far using the above set up I noticed that dust only builds
up at the front filter. Is my fan setup ok?

or what else could be done to optimize it

 

[DeenzX]

Yeah thats why i mentioned a plastic board to partition the 2 fans so the intake air gets directed downwards to be caught by the front fans and pushed to the back which then gets sucked out by the 2 exhaust
Looks might be affected tho

Since it is the top fan, may I ask if the format is like what is illustrated @ OP?
I think you can put the intake nearer to the CPU fan so it provides constant fresh air to the processor. The hot air will hopefully be exhausted immediately, but hopefully not sucked in by the intake again. That will certainly be disastrous!
I personally don't like top intakes as it may attract more dust and tiny particles due to gravity.

 

[DeenzX]

I'm using a corsair 540

so far using the above set up I noticed that dust only builds
up at the front filter. Is my fan setup ok?

or what else could be done to optimize it

I have found a thread on another forum that specifically talked about 140MM fans. The writer says that 140MM are in fact weaker despite the size, so they are used for exhausts.

Might wanna check it out.
OCN Dave's Air Cooling Guide - Updated

 

[Phelan]

No, it does not mean a 140mm fan is weaker than a 120mm. Different fan blades are designed for different purposes. Some fans are meant for static pressure while some are optimized for airflow. 120mm is preferred for pressure optimised fans because of the smaller area that the air is forced through.

Corsair has two fan models in 120mm, the SP120 and AF120. The SP has a lower CFM rating than the AF model but it generates a higher pressure zone AFTER the blades, not before it. SP fans are generally used if the air needs to be forced through a space just after it, that is 'obstructed' in a sense, such as a radiator or hard drive cage.