Positive air pressure case setup question.

[Solid State Soul ( SSS )]

Hello and goodday

am planning to build a PC using the fractal design Mechify C with super positive air pressure setup 3 front intakes - 3 top intakes - and one exhaust on the rear. Do you think that is fine for positive air pressure and good temps ?

Any downsides about this ?


The fans i will be using are the noctua S12A cause they push the highest airflow out of any 1200 rpm fan out their, but if you know a better alternative please comment it.

 

[IceScreamer]

As far as I know Meshify C has only 2 top intakes. Looking at the spec sheet of the case, the ideal setup would be 3 intakes in the front and one intake on the bottom with exhausts being the top and the rear.

 

[Solid State Soul ( SSS )]

As far as I know Meshify C has only 2 top intakes. Looking at the spec sheet of the case, the ideal setup would be 3 intakes in the front and one intake on the bottom with exhausts being the top and the rear.

I see many people saying that top should be exhaust but i just dont get it. it makes sense for a radiator but with an air tower cooler wouldn't it makes things better cause the top fans blow cool air over the top of a tower cooler, ddr4 memory and motherboard VRM area, their for a lower temps no ?

 

[IceScreamer]

I see many people saying that top should be exhaust but i just dont get it. it makes sense for a radiator but with an air tower cooler wouldn't it makes things better cause the top fans blow cool air over the top of a tower cooler their for a lower temps no ?

While that is true the hot air rises and it is easier to be expelled through the top. Multiple intakes around the air cooler could possibly create a turbulence and reduce the effectiveness of the cooler itself, or at least I've heard that could happen.

 

[Solid State Soul ( SSS )]

While that is true the hot air rises and it is easier to be expelled through the top. Multiple intakes around the air cooler could possibly create a turbulence and reduce the effectiveness of the cooler itself, or at least I've heard that could happen.

https://www.silverstonetek.com/techtalk_cont.php?tid=wh_positive&area=en

According to silverstone own diagram. It tells a setup slimier of mine is indeed a good positive pressure !

 

[IceScreamer]

https://www.silverstonetek.com/techtalk_cont.php?tid=wh_positive&area=en

According to silverstone own diagram. It tells a setup slimier of mine is indeed a good positive pressure !

Huh, nice find. I guess you could try both ways, and check the temps and/or dust buildup, would be a great experiment.

 

[Solid State Soul ( SSS )]

So here is how i see things working for my setup : the only heat source in the top area of the case is the cpu tower heatsink, the cpu heatsink fans blow hot air over to the rear exhaust fan and that fan sinks that hot out and exhaust it out. Now the bottom side of the case heat will be of coarse the graphics card. A high number of intake fans will create lots of air pressure that helps the hot air of the gpu being exhausted trough the case vents ( showing in the picture below ) not occupied by case fans. These vents can become either exhaust or intake depending on whether the chassis has positive or negative air pressure. my case has lots of intake that those become exhaust.

 

[Vayra86]

This is already the third place you're asking this question.

Why?! I've reported your other topic and asked for a merge.

https://www.silverstonetek.com/techtalk_cont.php?tid=wh_positive&area=en

According to silverstone own diagram. It tells a setup slimier of mine is indeed a good positive pressure !

That diagram is a 'right versus wrong' diagram showing how dust gets into a rig with negative pressure and no filters. Not an example of ideal airflow setups.

And it finishes with two case examples that are built for positive pressure setups. So its just basically just an ad for Silverstone, not a guide on ideal setups.

 

[Solid State Soul ( SSS )]

This is already the third place you're asking this question.

Why?! I've reported your other topic and asked for a merge.



That diagram is a 'right versus wrong' diagram showing how dust gets into a rig with negative pressure and no filters. Not an example of ideal airflow setups.

And it finishes with two case examples that are built for positive pressure setups. So its just basically just an ad for Silverstone, not a guide on ideal setups.

No. it show how an actual positive pressure configurations drawing air from filtered intakes and exhausting hot air trough the small vents due to high air pressure inside the case. results in low dust build up

The other one shows how air is entering the case trough unfiltered vents due to lots of exhaust fans, since air is entering trough unfiltered vents it results in high dust build up. simple as that

 

[newtekie1]

In my experience, you want positive pressure to help with dust but you don't want massive positive pressure. You still want it to be close to equal pressure, otherwise you have fans fighting too much pressure, typical case fans are not designed for pressure they are designed for airflow. Also, you don't want to put any intake fans where there isn't a dust filter(not really an issue with the Meshify C). You also still want to maintain somewhat of a smooth flow of air through the case, generally best going front to back. So having fans blowing downward from the top will only serve to disrupt the smooth airflow.

With the Meshify C, I would put 2 fans in the font. I know, you thinking, but why not 3. Simple, the 3rd fan, the bottom one, is almost entirely going into the PSU shroud, it is basically wasted, because nothing down there really needs that air, and you'll just end up with your extra PSU wires being coated in dust(yes, even with a dust filter). So, I would do 2 140mm fans in the font. Then I'd do 2 120mm, one in the back and one in the back slot of the top.

 

[Bill_Bright]

3 top intakes

I see many people saying that top should be exhaust but i just dont get it.

You want the top fans to exhaust so you are working with the Laws of Physics, not against them. Warm air rises. So naturally, heat inside the case will try to rise. If your top fan are intakes, they are blowing that heat back into the center of the case instead of helping it quickly escape.

Frankly, there is (or "was" - look at the date of that SilverStone article) way too much emphasis positive and negative air flow.

I'm with Newtekie1. You are looking for maximum "flow" through the case. That is achieved best with balanced or close to equal pressure. A little over-pressure is good. Too much of anything is not.

Two quiet 140mm fans in front pulling cool air in and one in back exhausting heated air out is what I would do. And if necessary to keep from overheating, one "blowhole" (top fan) exhausting heated air out. But with a decent case, I don't see why you would need the blowhole fan.

since air is entering trough unfiltered vents it results in high dust build up. simple as that

It is no where near as simple as that. What components do you have inside this case? Do you live in a very dusty environment and keep your windows open most of the time? Do you have multiple pets and little kids running around all the time stirring up dust? Is your case not filtered? Do you not keep your house clean?

High dust build-up is a thing of the past with filtered cases, unless you go years without opening the case for a proper cleaning - even if you have multiple pets and rugrats running about.

If you have just two intake fans in front, and one exhaust in back (and maybe exhaust help from the PSU fan), you will force the vast majority of air to come through front filtered vents. That's a good thing. They are simple to clean!

Over the last couple years we have used almost exclusively Fractal Design cases. I love them. The front filters work great.

And while I also love FD fans because they are so quiet while still moving massive amounts of air, I still hate fan noise. I mean, I really hate fan noise. And contrary to what many seem to believe, or just want us to believe, it is not necessary to get your temps as low a humanly possible. Your processor will NOT perform better, be more stable, or last longer if running at 25°C than it would if running at 50°C. As long as your CPU and other components are operating comfortably within their specified (and designed!) normal operating range, you have done your job. All cooler temps get you at that point is bragging rights.

See the "Heat" line in my signature to note I take heat seriously before you decide I don't know what I am talking about or think I'm trying to blow smoke up your a$$.

 

[Vayra86]

No. it show how an actual positive pressure configurations drawing air from filtered intakes and exhausting hot air trough the small vents due to high air pressure inside the case. results in low dust build up

The other one shows how air is entering the case trough unfiltered vents due to lots of exhaust fans, since air is entering trough unfiltered vents it results in high dust build up. simple as that

I think we have all concluded here that negative pressure setups are not beneficial, and that is also what Silverstone is implying with the whole article

https://www.techpowerup.com/forums/threads/positive-air-pressure-setup-question.249821/#post-3946376

In response to your last two lines in that post:
you've proven yourself how it works Its because people compare products based on the specs listed by company websites, and comparison sites and webshops copy those specs 1:1 because they are lazy, end result, you buy the stuff with the highest number. Then its up to reviewers to paint the real picture, and up to the consumer to do the proper research...

Another nice one is that 'testing methodology becomes more advanced over time' which actually means: 'we got caught and now we're displaying the actual numbers, or at least closer to reality'. You can look at any random product for proof: a notable one being car exhaust fumes. Some companies wanted that green eco sticker so badly they faked the tests

 

[EarthDog]

I think we have all concluded here that negative pressure setups are not beneficial...

We did? Speak for yourself.



The funny thing is, a PC case isnt remotely sealed so pressure differences are negligible if we re being literal. One of the few things 'positive pressure' does different is keep dust from going in from the cracks of the case. That's it (I tested this with two systems same case, different fan setups). Otherwise for cooling, it depends on the case and cooling needs as to which is better.

Generally, front/sides = intake, top/rear = exhaust. Unless the case mfg says otherwise, I'd follow that method. I prefer having a bit more CFM exhaust than intake (but not by much) as in my situations has show better temperatures. I could care less about the little difference it made for me in regards to dust.

 

[Bill_Bright]

The funny thing is, a PC case isnt remotely sealed so pressure differences are negligible

Ummm, not true - unless you mean before any fans are powered up. Depending on how fans are oriented, you can have extreme over or extreme under pressures in the case, or a balanced "flow".

 

[Solid State Soul ( SSS )]

I think we have all concluded here that negative pressure setups are not beneficial, and that is also what Silverstone is implying with the whole article

https://www.techpowerup.com/forums/threads/positive-air-pressure-setup-question.249821/#post-3946376

In response to your last two lines in that post:
you've proven yourself how it works Its because people compare products based on the specs listed by company websites, and comparison sites and webshops copy those specs 1:1 because they are lazy, end result, you buy the stuff with the highest number. Then its up to reviewers to paint the real picture, and up to the consumer to do the proper research...

Another nice one is that 'testing methodology becomes more advanced over time' which actually means: 'we got caught and now we're displaying the actual numbers, or at least closer to reality'. You can look at any random product for proof: a notable one being car exhaust fumes. Some companies wanted that green eco sticker so badly they faked the tests

Well you own silent-wings 3 fans in addition to the ones inside the dark rock pro 3 so tell, noise wise are they near what that test concludes ?

 

[Vayra86]

Well you own silent-wings 3 fans in addition to the ones inside the dark rock pro 3 so tell, noise wise are they near what that test concludes ?

I never hear them unless I put them on 70%> speeds. And even then its a low-key whisper, you never hear the motor.

For comparison, my MSI Gaming X which is also a very quiet GPU drowns them out completely.

 

[jboydgolfer]

Hello and goodday

am planning to build a PC using the fractal design Mechify C with super positive air pressure setup 3 front intakes - 3 top intakes - and one exhaust on the rear. Do you think that is fine for positive air pressure and good temps ?

Any downsides about this ?

i have this case, i have it set up as follows and it is SUPER cold.

2x 140mm intakes in front of 280mm Rad
1x120mm exhaust rear
1x120mm exhaust top/rear. (not in pic, but it is installed)

it has a different GPU now, but the rest is still the same.

 

[EarthDog]

Ummm, not true - unless you mean before any fans are powered up. Depending on how fans are oriented, you can have extreme over or extreme under pressures in the case, or a balanced "flow".

Measure the difference in pressure within the case and outside and report back with your findings.

 

[Mayclore]

I have two front intakes behind a filter and a rear exhaust, but my GTX 1080 is the sealed blower type and shoots all of its heat out the back.

I've often wondered if switching my front fans to be top intakes (where I also have a filter) would make any difference with the Mugen 5 I have, but I've never tried it.

 

[EarthDog]

You may get cooler temps on the cpu suits getting the freshest/coolest air, but where that heated air now going easily?

These guys above talk about airFlow and that is the key.

 

[Vayra86]

I have two front intakes behind a filter and a rear exhaust, but my GTX 1080 is the sealed blower type and shoots all of its heat out the back.

I've often wondered if switching my front fans to be top intakes (where I also have a filter) would make any difference with the Mugen 5 I have, but I've never tried it.

Unlikely. As posted earlier, heat rises and top intake would also not benefit your Mugen 5's airflow direction which is front to back. The GPU also benefits from front to back because the backplate/PCB gets hot as well, front feeds both the GPU intake and the topside.

 

[rtwjunkie]

I see many people saying that top should be exhaust but i just dont get it. it makes sense for a radiator but with an air tower cooler wouldn't it makes things better cause the top fans blow cool air over the top of a tower cooler, ddr4 memory and motherboard VRM area, their for a lower temps no ?

No. What makes sense is that is the natural route for air: heat rises. 2 blowing in from the top meeting the three from the front will produce a lot of turbulence in the center, probably raising temperature, not lowering it.

Also, what fans you use can make a difference. You want airflow, but you don’t want a hurricane, either in strength or noise. For that reason my total intakes have slightly more CFM of air movement than the different exhaust fans with an aggregate lower CFM out. It’s only a slight differentiation, but enough to result in a positive pressure, more importantly directing airflow and the heat air absorbs where I want it to go.

This forces the extra air out of any cracks, and I end up with hardly any dust in my systems. Every piece of hardware I have sold on TPU is testament to that.

 

[jboydgolfer]

I have the exact case you're talking about, I've tried several different airflow set up's ,the one I have in the picture above works very well. Nuff said.

The top fans should definitely be exhaust ,unless you have your PC upside down or something.

 

[Bill_Bright]

Measure the difference in pressure within the case and outside and report back with your findings.

That's just silly. No measuring needed. Simple common sense will do.

Point all your fans inside and you will have extreme over pressure. Point all your fans to exhaust and you will have extreme under pressure. Point some in and some out and you will have (more or less) a balanced flow.

These guys above talk about airFlow and that is the key.

Exactly.

 

[infrared]

Point all your fans inside and you will have extreme over pressure

No, the most you'll get, with fans at 100%, is simply the static pressure rating of the weakest fan. Which isn't a significan't pressure. I'm talking much less than even 1psi. Computer fans aren't compressors.

Edit - the max static pressure of a corsair ML120 at 100% is 4.2 mmH2O, which is 0.00597PSI. I'd say that's definitely an insignificant and difficult to measure amount.

Edit 2 for OP - I personally aim for a very slight positive pressure setup. The closer you are to a completely ballanced setup, the more airflow you'll have, if you aim for loads of static pressure you're simply restricting airflow on the exhaust side. You only need slight positive pressure to prevent dust coming in through unfiltered openings.
My current system pulls in through 240mm radiators top and bottom, so 4x 120mm fans, through filters and radiators which obviously restricts them a little bit, and then 1x 140mm fan as an exhaust with no restrictions on it. Works perfectly. But then I reckon you could have a fairly unoptimal setup and still claim it works perfectly, the differece won't be a lot unless you have some serious restrictions, like tempered glass covering the entire intake, that seems to be fashonable for some reason!