How do case fans work?

[Or Aviram]

I just finished building my PC (except for the graphics card, because I am waiting to get the 1080 FTW edition, but aunt gave me an old card just so I will check if it works), and when I powered it on, I got a surprise... The airflow of the case fans got out of the case. It was also much colder to put my hand on the outside where the fan was than the inside.

I thought case fans are suppose to point their airflow into the case, so it will cool some stuff, and give it's air to the radiator fans (I put it in a way that it takes air from the case and points it up to the radiator), or the GPU fans, maybe on the way also help cooling the RAM and motherboard. The bios at the start said the CPU was at 32 degrees C, but after a few minutes it already said 35, which means it's getting up pretty fast...

The weird thing, is that the fans came like that with the case (the Cooler Master Mastercase Pro 5), I did not change ANYTHING.

 

But maybe it is actually suppose to be like that, because Cooler Master knows better than me... Is it suppose to be like that? If not, please tell me and I will change that... But if it is, how do they work? How do they help cooling like that?

[another random person]

8 minutes ago, Or Aviram said:

I just finished building my PC (except for the graphics card, because I am waiting to get the 1080 FTW edition, but aunt gave me an old card just so I will check if it works), and when I powered it on, I got a surprise... The airflow of the case fans got out of the case. It was also much colder to put my hand on the outside where the fan was than the inside.

I thought case fans are suppose to point their airflow into the case, so it will cool some stuff, and give it's air to the radiator fans (I put it in a way that it takes air from the case and points it up to the radiator), or the GPU fans, maybe on the way also help cooling the RAM and motherboard. The bios at the start said the CPU was at 32 degrees C, but after a few minutes it already said 35, which means it's getting up pretty fast...

The weird thing, is that the fans came like that with the case (the Cooler Master Mastercase Pro 5), I did not change ANYTHING.

 

But maybe it is actually suppose to be like that, because Cooler Master knows better than me... Is it suppose to be like that? If not, please tell me and I will change that... But if it is, how do they work? How do they help cooling like that?

 

Never put the fans to blow air out. My fans came like that too on my Deepcool case and I quickly flipped it around. Always remember cool air in and not hot air out. 

Also hot air from inside the case being blown through a RAD is a horrible idea. Radiators need cool air from the outside of the case.

[2Fast2Quik]

6 minutes ago, another random person said:

Never put the fans to blow air out. My fans came like that too on my Deepcool case and I quickly flipped it around. Always remember cool air in and not hot air out. 

Also hot air from inside the case being blown through a RAD is a horrible idea. Radiators need cool air from the outside of the case.

 

Wait, so all of your case fans are blowing air in? That's pretty terrible, I believe Linus did a video about this topic explaining how it's better to have an equal amount of intake vs exhaust. 

[henkka_scorpio]

A through in-out is best for example, i have 2 fans in the front to push air in and two in the back to push air out. If all fans push out, it will get a lot of dust inside, and if all fans push inside it will have a higher pressure inside and air will go out of every hole.

[another random person]

2 minutes ago, 2Fast2Quik said:

Wait, so all of your case fans are blowing air in? That's pretty terrible, I believe Linus did a video about this topic explaining how it's better to have an equal amount of intake vs exhaust. 

 

i only have 2 fans. 

[2Fast2Quik]

Just now, another random person said:

i only have 2 fans. 

Where are they and are they intake or exhaust?

[another random person]

3 minutes ago, 2Fast2Quik said:

Where are they and are they intake or exhaust?

my case has 6 fan mounting positions, one of my fans is in the front and the other is in the back with my regretful h55 rad.

which leaves 4 open holes.

[henkka_scorpio]

put front fan in and back fan blowing out or the other way around.

[2Fast2Quik]

Just now, another random person said:

my case has 6 fan mounting positions, one of my fans is in the front and the other is in the back with my regretful h55 rad.

which leaves 4 open holes.

 

And they are both blowing air in? hat's pretty bad, what you should do I have the one in the back blow air out, and the one in the front blow air in.

[2Fast2Quik]

When you have case fans you should try to balance the intake to exhaust so do what henkka said. 

[another random person]

1 minute ago, 2Fast2Quik said:

And they are both blowing air in? hat's pretty bad, what you should do I have the one in the back blow air out, and the one in the front blow air in.

Dont worry about it, im getting two fans soon and im going to put them at exhaust

[2Fast2Quik]

18 minutes ago, another random person said:

Never put the fans to blow air out. My fans came like that too on my Deepcool case and I quickly flipped it around. Always remember cool air in and not hot air out. 

Also hot air from inside the case being blown through a RAD is a horrible idea. Radiators need cool air from the outside of the case.

 

That still doesn't excuse what you were saying as advice, or perhaps I did not understand, howcome you were advising not to blow hot air out?

[Or Aviram]

I switched one and  it went down to 31-33 degrees C, so I guess it worked.

I have one fan in the back that's an intake, one in the front as an intake, another one in the front as an exhaust, and two more on top attached to the radiator as exhaust. Is that good?

 

And just so you will get notified, I will do that...:

@2Fast2Quik @another random person @henkka_scorpio

[2Fast2Quik]

It's not good. If you have 2 fans in the front one as intake and one as exhaust the air will loop and that is NOT what you want. What you should do is have the one in the back as exhaust, the 2 in the front as intake and the 2 on the top as exhaust. 

[another random person]

2 minutes ago, 2Fast2Quik said:

It's not good. If you have 2 fans in the front one as intake and one as exhaust the air will loop and that is NOT what you want. What you should do is have the one in the back as exhaust, the 2 in the front as intake and the 2 on the top as exhaust. 

 

good point i forgot about air looping, just make sure the radiator fans are intake (according to linus in an earlier video)

 

[2Fast2Quik]

1 minute ago, another random person said:

good point i forgot about air looping, just make sure the radiator fans are intake (according to linus in an earlier video)

 

 

Intake you say? Hmm, I guess for radiators it doesn't really matter, so it's up to you op, however I would still recommend exhaust as intake can cause complications with vrm cooling.

[another random person]

1 minute ago, 2Fast2Quik said:

Intake you say? Hmm, I guess for radiators it doesn't really matter, so it's up to you op, however I would still recommend exhaust as intake can cause complications with vrm cooling.

 

Well, hey if anything goes wrong blame linus

[2Fast2Quik]

1 minute ago, another random person said:

Well, hey if anything goes wrong blame linus

Im gonna do research righ tnow. OP DONT WORRY, I AM HERE!

[Or Aviram]

14 minutes ago, 2Fast2Quik said:

It's not good. If you have 2 fans in the front one as intake and one as exhaust the air will loop and that is NOT what you want. What you should do is have the one in the back as exhaust, the 2 in the front as intake and the 2 on the top as exhaust. 

But then the fans of the radiator are not going to get much airflow, and the CPU will be hotter. Will it work if I will have the two fans in the front and top an exhaust, and the one in the back an intake? Or... It doesn't feel that balanced to me, so maybe the two in the front an intake and the one in the back an exhaust (still the top will be an exhaust, that's what Corsair recommends with that cooler)? But I have a hard drive cage which blocks a part of the airflow, but I don't know how much it matters...

[2Fast2Quik]

1 minute ago, Or Aviram said:

But then the fans of the radiator are not going to get much airflow, and the CPU will be hotter. Will it work if I will have the two fans in the front and top an exhaust, and the one in the back an intake? Or... It doesn't feel that balanced to me, so maybe the two in the front an intake and the one in the back an exhaust (still the top will be an exhaust, that's what Corsair recommends with that cooler)? But I have a hard drive cage which blocks a part of the airflow, but I don't know how much it matters...

 

What you need to remember is that airflow spreads and follows through nooks and crannies. Having more exhaust is better becuause more hot air is leaving and some cool air is entering. The CPU will not be hotter as the hot air is leaving the case, computer cooling is not like blowing a fan to cool down paint. It's more like moving steam or vapor away from a plate and moving good air near the plate, understand?

[2Fast2Quik]

Additionally your fans on the top should be exhaust Pushing air, so they should be underneath the radiator.

[Or Aviram]

3 minutes ago, 2Fast2Quik said:

What you need to remember is that airflow spreads and follows through nooks and crannies. Having more exhaust is better becuause more hot air is leaving and some cool air is entering. The CPU will not be hotter as the hot air is leaving the case, computer cooling is not like blowing a fan to cool down paint. It's more like moving steam or vapor away from a plate and moving good air near the plate, understand?

So it will be good to have the two fans on the front an exhaust and the one in the back an intake? And the fans on the radiator for sure will be an exhaust under the radiator which is at the top of the case. It already is there, actually, and I won't change it.

[2Fast2Quik]

The fans in the front should be intake.

Fans in the back, exhaust.

[Or Aviram]

28 minutes ago, 2Fast2Quik said:

The fans in the front should be intake.

Fans in the back, exhaust.

Did what you said. The idle temperature of the CPU at the start was 31 - 32 degrees, but I kept the computer open and went to eat, so I will know if it stays like that. It doesn't. When I came back it was at 37 degrees, so there must be something wrong. The CPU is the i7 5820K, which can get really hot since it's a hex-core CPU, but I am still planning to overclock it to something like 4.4 - 4.8 GHz, which I doubt I will be able to do like that. The cooler is the Corsair H100i GTX, which I heard can cool stuff very awesomely, so why is it so hot?

[Or Aviram]

@2Fast2Quik And I still think it makes sense to put the fan in the back as an intake, but then I don't know how I can balance the intake and exhaust...