Intake or exhaust? Case fans setup dillema

[DRagor]

Short version: Is it better to create positive pressure by having more intake fans, or negative pressure by having more exhaust fans? Which is better for temperature and dust problem?

Long story:
My new build is ready for case fans placement, but I'm wondering which setup to choose. I have Raijintek Arcadia case (yeah, cheap thing, but has all I need), which has four fan slots: front, back and 2 top. PSU is running on its own air flow at the bottom. The fans: front is 95 CFM, top#1 is 95 CFM, top #2 is 52 CFM, and back is 65 CFM. Can't swap their positions (yeah cheap case problem), only direction.
So possible setups are:
A> front and back intake, top exhaust - 2 vs 2, but setting back as intake sounds stupid to me
B> front and top#1 intake, back and top#2 exhaust - again 2 vs 2, but I'm afraid top#1 will suck the hot air top#2 exhaust, since #1 is stronger ...
and the real ones:
C> front and top intake, back exhaust - so 3 intake 1 exhaust, big positive pressure?
D> front intake, rest exhaust - only 1 intake, isn't it going to choke the airflow?
and two more, crazy options:
E> could try an extra 80mm fan at front just below DVD, intake I guess, but since there is absolutely nothing to screw it to, it would be a nightmare to mount it
F> could just drill a couple of holes in left side panel and put extra fan there, probably exhaust, at the height of GPU

So what you guys think? I would add that I'm more concerned with dust rather then temperature.

 

[Inkiad]

I would go with A. Your GPU will also act as an exhaust. Front intake will mostly help cool GPU, rear intake will help cool CPU.

 

[Dooop805]

A

 

[aquielisunari]

Short version: Is it better to create positive pressure by having more intake fans, or negative pressure by having more exhaust fans? Which is better for temperature and dust problem?

Long story:
My new build is ready for case fans placement, but I'm wondering which setup to choose. I have Raijintek Arcadia case (yeah, cheap thing, but has all I need), which has four fan slots: front, back and 2 top. PSU is running on its own air flow at the bottom. The fans: front is 95 CFM, top#1 is 95 CFM, top #2 is 52 CFM, and back is 65 CFM. Can't swap their positions (yeah cheap case problem), only direction.
So possible setups are:
A> front and back intake, top exhaust - 2 vs 2, but setting back as intake sounds stupid to me
B> front and top#1 intake, back and top#2 exhaust - again 2 vs 2, but I'm afraid top#1 will suck the hot air top#2 exhaust, since #1 is stronger ...
and the real ones:
C> front and top intake, back exhaust - so 3 intake 1 exhaust, big positive pressure?
D> front intake, rest exhaust - only 1 intake, isn't it going to choke the airflow?
and two more, crazy options:
E> could try an extra 80mm fan at front just below DVD, intake I guess, but since there is absolutely nothing to screw it to, it would be a nightmare to mount it
F> could just drill a couple of holes in left side panel and put extra fan there, probably exhaust, at the height of GPU

So what you guys think? I would add that I'm more concerned with dust rather then temperature.

Front and back 95CFM. Front intake and the rear exhaust. Top two are also exhaust.

Why? Heat rises. So allow the two weaker fans(on low) to exhaust any residual heat. The rear exhaust is helpful for exhausting the CPU heatsink's exhaust. Dust falls. Making the top intake would feed your components dust. They prefer electricity and fresh air over dust and choked up heatsink fins.

 

[DRagor]

Thanks for your answers.

Inkiad - that was my original idea, but I realized that rear intake would take hot air that PSU exhausts; not to mention all that dust that's behind my comp

aquielisunari - my fear is that setting 3 fans on exhaust will create so much negative pressure inside case that it will start sucking dust through all holes like a vacuum cleaner

 

[aquielisunari]

Thanks for your answers.

Inkiad - that was my original idea, but I realized that rear intake would take hot air that PSU exhausts; not to mention all that dust that's behind my comp

aquielisunari - my fear is that setting 3 fans on exhaust will create so much negative pressure inside case that it will start sucking dust through all holes like a vacuum cleaner

Just an opinion. I prefer the front to back airflow to be the most important. The top two fans on my Vivo Titan are set to low exhaust. I have the rear exhaust which I can also control but usually leave on low. My front two fans are of course set to intake. With the steel mesh filters in place dust will eventually accumulate inside the case. It is part of maintenance for me. Keeping your house's AC filter clean helps to keep dust to a minimum. Not too helpful in winter but maintenance is a PC user's responsibility. Most everything needs a certain amount of maintenance. It could be seen as accepting the lesser evil. Canned air and a micro-fiber dust free cloth are just part and parcel of keeping my PC happy. It's the same with Windows. Can't just use the OS. Maintenance is needed to keep its speed and efficiency at nominal levels. How many times has one heard 'my PC used to be fast'?

Which CPU cooler do you have? That makes a huge difference. I have the Evo 212 set so that the front fresh air is pushed through it's fins and a second fan pulls that air and pushes it to the rear exhaust.

If your CPU cooler blows straight up then you can have the front and back set to intake and the top to exhaust. Another fan down by the GFX card on the side panel can feed it more air. I wouldn't have two fans blowing towards each other and a third blowing at that airflow.

I kept things simple. Front to back and a couple low power fan on top that deal with the hot air that naturally rises.

 

[DRagor]

Which CPU cooler do you have? That makes a huge difference. I have the Evo 212 set so that the front fresh air is pushed through it's fins and a second fan pulls that air and pushes it to the rear exhaust.

If your CPU cooler blows straight up then you can have the front and back set to intake and the top to exhaust. Another fan down by the GFX card on the side panel can feed it more air. I wouldn't have two fans blowing towards each other and a third blowing at that airflow.

I kept things simple. Front to back and a couple low power fan on top that deal with the hot air that naturally rises.

Just an old Silentium HE924. Not a big thing, but should be more then enough for i5-7500. Currently set up front to back. But it can be turned into any direction, in 60 degrees increment. Might add 2nd fan to it to create push-pull if necessary.
Keeping things simple would be nice. It's just my brain that sometimes comes up with weird ideas

 

[amtseung]

I'd personally put one fan in front (whichever has greatest CFM through restrictions, because look at those drive cages), and one in the top back, and leave it like that.

In my S340, I once attempted to make the front 2 fans intakes, back intake, top exhaust, and what I found was that the air being pulled in from the back simply went straight out the top. Just like any other fluid, air flow will always take the path of least resistance, so the air being sucked in the back will go straight out the top instead of cooling anything. If anything, your cooling performance will decrease.

If you have a tower CPU cooler, directional airflow is pretty important. A rear intake would directly impeded the airflow trying to leave a CPU cooler mounted in traditional fashion. If you have a downdraft CPU cooler, I'd recommend creating a duct from CPU fan straight to a hole cut into the side panel. This worked wonders in my Rosewill FBM-01 with a stock AMD cooler, pre-wraith. I watched my overclocked A6-5400k load temps drop by over 10C just by feeding it fresh air. All I did was cut up some cardboard and tape it into a square tube that friction fit onto the fan, and used a dremel to carve out a square so the cardboard tube could stick out, like a snorkel. Loud AF, but really good cooling for a crappy stock AMD cooler. You can always be fancier and glue a black PVC pipe to the side panel, or get creative. 😉

If you have a tower CPU cooler that sits neutral like a Hyper212 or T4 or the like, not offset like the Cryorig offerings, you might be able to rotate it 90 degrees so the fan exhausts upwards, because heat rises. Fans in pull on CPU tower heat sinks tend to offer slightly better thermals, at least from my experimentation. If you're not too worried about CPU temps, you can mount the CPU fan in push, between the heat sink and the top of the GPU, which will help cool really hot GPU's as well. With this orientation, a single top exhaust, while blocking off the rear fan slot with cardboard or something, will actually help overall component temps except the motherboard VRM's. Again, an indication that directional airflow is more important than just having lots of it.

Obligatory YMMV here.

Negative case pressure is never bad for component cooling, but unless you can seal your side panels and filter every other opening there is (including the PSU vents), if you live in a dusty area like I do, you'll have crazy dust build up in no time at all.

Just food for thought.

/essay

 

[DRagor]

I'd personally put one fan in front (whichever has greatest CFM through restrictions, because look at those drive cages), and one in the top back, and leave it like that.

In my S340, I once attempted to make the front 2 fans intakes, back intake, top exhaust, and what I found was that the air being pulled in from the back simply went straight out the top. Just like any other fluid, air flow will always take the path of least resistance, so the air being sucked in the back will go straight out the top instead of cooling anything. If anything, your cooling performance will decrease.

So that kicks out option A pretty much

Obligatory YMMV here.

Negative case pressure is never bad for component cooling, but unless you can seal your side panels and filter every other opening there is (including the PSU vents), if you live in a dusty area like I do, you'll have crazy dust build up in no time at all.

Just food for thought.

/essay

I guess that's where good old duct tape comes in My house has very low humidity, in summer it falls below 50% easily, so lot of dust in the air.
Thanks, now I'll have even more thoughts; like it was in 'Last samurai' - "too many minds"?

 

[aquielisunari]

I'd personally put one fan in front (whichever has greatest CFM through restrictions, because look at those drive cages), and one in the top back, and leave it like that.

In my S340, I once attempted to make the front 2 fans intakes, back intake, top exhaust, and what I found was that the air being pulled in from the back simply went straight out the top. Just like any other fluid, air flow will always take the path of least resistance, so the air being sucked in the back will go straight out the top instead of cooling anything. If anything, your cooling performance will decrease.

So that kicks out option A pretty much

Obligatory YMMV here.

Negative case pressure is never bad for component cooling, but unless you can seal your side panels and filter every other opening there is (including the PSU vents), if you live in a dusty area like I do, you'll have crazy dust build up in no time at all.

Just food for thought.

/essay

I guess that's where good old duct tape comes in My house has very low humidity, in summer it falls below 50% easily, so lot of dust in the air.
Thanks, now I'll have even more thoughts; like it was in 'Last samurai' - "too many minds"?

Near the end when he helped his friend commit seppuku, that hurt. Before that when the Gatling gun was taking so many lives and the Japanese Officer wept? Wow. Heart-wrenching.

The mind is a battlefield with many voices. Taking control of that battlefield is possible. The constant stream of randomness? Controllable. Cooling your PC? The easy part.

 

[DRagor]

Me being me, I could not just take a simple solution
But here common sense and laws of physics are going to limit my creativity. So I decided to go with two big fans set front-intake and rear-exhaust, plus small one exhaust at top just over CPU heat sink. Will see how it works, and possibly do some tweaking later.
Thanks for help, too bad could not give 2 best solutions.

 

[aquielisunari]

Me being me, I could not just take a simple solution
But here common sense and laws of physics are going to limit my creativity. So I decided to go with two big fans set front-intake and rear-exhaust, plus small one exhaust at top just over CPU heat sink. Will see how it works, and possibly do some tweaking later.
Thanks for help, too bad could not give 2 best solutions.

Maybe a mesh filter over the unpopulated fans space(s). They sell many different sizes and types of fan filters. I'd have it in place to help with deterring any dust from settling in and taking up residency.

Thank you for the update. How's the PC temps.? When you get to my temps you know you have a good fan setup

gotta get a second opinion

 

[DRagor]

As surprising as it sounds, my 30$ case DO come with mesh filters
Will start a new machine tomorrow. Kinda hard feeling to part with old one (10 y old!) and since I have only 1 keyboard and mouse, can't run them both.

 

[aquielisunari]

As surprising as it sounds, my 30$ case DO come with mesh filters
Will start a new machine tomorrow. Kinda hard feeling to part with old one (10 y old!) and since I have only 1 keyboard and mouse, can't run them both.

Just make sure the old one finds a loving home. They don't like to be prisoners in closets, garages and attics. Sell or donate. Find it a new place and you can be happy it's has found a new forever home. I am so not about to cry either.

 

[DRagor]

Just make sure the old one finds a loving home. They don't like to be prisoners in closets, garages and attics. Sell or donate. Find it a new place and you can be happy it's has found a new forever home. I am so not about to cry either.

Yeah that's the plan. Maybe it will bring me back enough money to pay for those extra fans I bought. Fans cost me more then paid for case ... now when I look at it, I think I must be mad.

 

[DRagor]

Sooo, new machine up and running... and I'm not happy with temps.
Run occp (linpack) for several minutes, CPU was stable below 60 C, but VRM went up to almost 70 C. No matter how I was going to set fans in SIV, only CPU and front were speeding. The back and top were just sitting at about 50%. The back one should be going up to cool VRM, but nooo.
As a side note CM JetFlo at full speed is loud as hell

 

[aquielisunari]

Sooo, new machine up and running... and I'm not happy with temps.
Run occp (linpack) for several minutes, CPU was stable below 60 C, but VRM went up to almost 70 C. No matter how I was going to set fans in SIV, only CPU and front were speeding. The back and top were just sitting at about 50%. The back one should be going up to cool VRM, but nooo.
As a side note CM JetFlo at full speed is loud as hell

There's always hardware https://www.amazon.com/Sentry-5-4-Inch-Controller-Cooling-AC-SEN-3-B1/dp/B00KJGYLNM/ref=sr_1_9?ie=UTF8&qid=1487795652