Discussion Thoughts on SilverStone's contrary-to-popular-opinion airflow advice?

May 31, 2020
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SilverStone has a webpage on optimal airflow that I think covers the basics pretty well, but one thing stuck out to me:



They explicitly advise against putting two exhaust fans perpendicular to one another because the fans will fight for air, causing "air pressure imbalance and reduced flow efficiency." This is a pretty commonly recommended fan setup in PC communities though, and some cases even come with fans pre-installed like that.

So is SilverStone right, and have people been setting up their cooling incorrectly? Maybe the distance required between the fans for them to be considered perpendicular is narrow enough that this doesn't apply to many cases? Or maybe the reduced flow efficiency effect is small enough that it doesn't really matter? I assume SilverStone has tested these setups for them to come out against the grain like this.
 
Silverstone has some AP series fans you might look at. The air doesn't actually go where you might think it does.
https://duckduckgo.com/?q=silverstone+air+penetrator+video&t=chromentp&ia=videos&iax=videos&iai=https://www.youtube.com/watch?v=8m8fC809TK0
It wouldn't be that hard to get a temperature monitoring utility, and flip your fans around and see what works for you.
But I would trust Silverstone over what ever other answers you may get here.

A man with one watch always knows what time it is. A man with 2 watches is never sure.
 
The link gives good advice.
You always need to get fresh air into the case for cooling.
In the example you showed, there is no intake in the poor case.

The best is intake in front and exhaust in the rear or possibly top.
Intake bottom and exhaust can work, but not many cases are designed that way.

I also favor positive pressure where all of the intake comes from one source and is filtered. That way, your pars stay cleaner.
 

rubix_1011

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The images also seem to suggest there are no other intake fans in the case, which is less common than it was 10 or 15 years ago, but not completely irrelevant.

However, I don't think that the two fans 'fighting for air' is as much of a reality as people assume it is or even as much of an issue of allowing for better case airflow by specifying a dedicated intake and exhaust fan as well as those being in close proximity to the CPU cooler which would benefit from it.

PC cases are not air tight and there will always be some form of method for ambient air to displace air being moved by fans. Removing fans or changing airflow will always have some form of consequence, some of which might require multiple tests to determine what works best with the hardware being used.
 
May 31, 2020
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I should clarify that the graphic only shows two fans because that's what's being discussed, not because SilverStone recommends or thinks it's common to have no front intake fans. The last graphic on the linked webpage shows a full fan setup, complete with front intake fans and the back exhaust/top intake setup they recommend.

However, I don't think that the two fans 'fighting for air' is as much of a reality as people assume it is or even as much of an issue of allowing for better case airflow by specifying a dedicated intake and exhaust fan as well as those being in close proximity to the CPU cooler which would benefit from it.
Can you rephrase this please? I'm not sure what you mean.
 

Zerk2012

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I should clarify that the graphic only shows two fans because that's what's being discussed, not because SilverStone recommends or thinks it's common to have no front intake fans. The last graphic on the linked webpage shows a full fan setup, complete with front intake fans and the back exhaust/top intake setup they recommend.


Can you rephrase this please? I'm not sure what you mean.
Personally I would remove the middle drive bay and add front intake fans and have the top and back blowing out. Using the case in the picture.

BUT you never actually listed the exact case your going to use you can't just use a generic flow diagram to get the best cooling!
 
May 31, 2020
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Personally I would remove the middle drive bay and add front intake fans and have the top and back blowing out. Using the case in the picture.

BUT you never actually listed the exact case your going to use you can't just use a generic flow diagram to get the best cooling!
I think there's been a misunderstanding - I'm not looking for advice on how to best cool a specific case. Like I said in the OP, I found it interesting that SilverStone advises against a fan setup that's commonly recommended in the PC building community, and wanted to hear people's thoughts on the matter.

SilverStone's recommendation to avoid putting exhaust fans perpendicular to one another doesn't have anything to do with drive bays or front intake fans, their only claim is that a back exhaust fan and a top rear exhaust fan will fight for air and impede flow efficiency.
 

Zerk2012

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I think there's been a misunderstanding - I'm not looking for advice on how to best cool a specific case. Like I said in the OP, I found it interesting that SilverStone advises against a fan setup that's commonly recommended in the PC building community, and wanted to hear people's thoughts on the matter.

SilverStone's recommendation to avoid putting exhaust fans perpendicular to one another doesn't have anything to do with drive bays or front intake fans, their only claim is that a back exhaust fan and a top rear exhaust fan will fight for air and impede flow efficiency.
That is not correct it depends on the case again a generic diagram of airflow. If you look at the bottom of your link it shows front intake and back output! All cases are going to very depending on the design.

Their a lot of cases today that don't even have the drive bays as they picture, ( PSU shroud, open front, drive bays inside the PSU shroud)

You could use a smoke machine to actually see the airflow and a heat detector to see the thermals using 5 different cases and have a lot of different results.

Then it would all be different if you were using a AIO cooler instead of air!
 
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May 31, 2020
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That is not correct it depends on the case again a generic diagram of airflow. If you look at the bottom of your link it shows front intake and back output! All cases are going to very depending on the design.

Their a lot of cases today that don't even have the drive bays as they picture, ( PSU shroud, open front, drive bays inside the PSU shroud)

You could use a smoke machine to actually see the airflow and a heat detector to see the thermals using 5 different cases and have a lot of different results.

Then it would all be different if you were using a AIO cooler instead of air!
I think you're getting hung up on the superfluous details in the diagram and ignoring the point SilverStone is trying to make. The graphic is meant to illustrate their point about perpendicular exhaust fans, not to make claims about front intake fans or drive bays.

I'm also not sure why you're bringing up that all cases vary depending on the design, or that things would be different with an AIO vs air cooling, or that a lot of recent cases don't even have drive bays. Nobody was arguing otherwise? The only thing you haven't touched on is the entire point of the thread in the first place: whether SilverStone is right that perpendicular exhaust fans, a commonly recommended setup, are bad for airflow.
 

AlexaKitty

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My setup is like this currently. Don't know if I should remove that top fan or switch it around as an intake, according to Silverstone's diagram. Or do I need not change anything at all?

I have no idea what to make of the replies to this thread.

Suggestions welcome.
 

madmatt30

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Personally never liked using top case mounts as exhausts, I absolutely agree with silverstone in the respect that you're causing disruption when running that setup you have.

Not necessarily with the rear exhaust but with the tower cpu cooler itself.

If you have good air intake from the front then a single rear exhaust fan is enough imo.

If you do have vented top fan mounts in the case then just leave them clear and let natural convection take care of the rest.

People seem intent on filling every fan slot in a case nowadays, the advent of top mounted vents was primarily for aio water cooling units imo not for exhaust fans when using an air cooler.

I do infact have a silverstone htpc case where I do use the top vent (actually on the side as the case lays flat) as an intake simply because its the only airflow I can get in there, that is an isolated case though (pun absolutely intended)
 
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AlexaKitty

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That's what I thought. My Noctua NF-A14 fans are arriving soon, I'll take out all the fans i currently have then install one exhaust in the rear, two as intakes on the mesh front and leave the top clear. We'll see if temps improve.
 

madmatt30

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I would expect temps to stay roughly the same rather than improve, what it will do though essentially is make the CPU cooler more efficient.

Not adverse to the way you have it set up if you limit those 2 exhausts to lower rpm.

I could waffle about airflow all day long in all honesty ;-)
The crux of it though is the clue is in the word 'flow'. Some assume that more fans = better, not always the case, all you're really trying to do is keep air moving from the front to the rear of the the case without dead spots.
 
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AlexaKitty

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I would expect temps to stay roughly the same rather than improve, what it will do though essentially is make the CPU cooler more efficient.

Not adverse to the way you have it set up if you limit those 2 exhausts to lower rpm.

I could waffle about airflow all day long in all honesty ;-)
The crux of it though is the clue is in the word 'flow'. Some assume that more fans = better, not always the case, all you're really trying to do is keep air moving from the front to the rear of the the case without dead spots.
The one exhaust on the top right now is actually at half the RPM of all the other fans since it's a 3-pin stock fan set on Voltage that came with the case that I decided to have up there because why not.

I am beginning to dig this 1 rear exhaust, 2 front intake idea though.

What I'm expecting is quieter operation and less dust in the case, rather than lower temps. My temps are great as they are, CPU under 29C on idle. And the GPU is under 39C on idle, compared to my previous prebuilt 45C on idle.
 

madmatt30

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The one exhaust on the top right now is actually at half the RPM of all the other fans since it's a 3-pin stock fan set on Voltage that came with the case that I decided to have up there because why not.

I am beginning to dig this 1 rear exhaust, 2 front intake idea though.

What I'm expecting is quieter operation and less dust in the case, rather than lower temps. My temps are great as they are, CPU under 29C on idle. And the GPU is under 39C on idle, compared to my previous prebuilt 45C on idle.
I'm with you, you have an excellent case for airflow there, the mesh front makes all the difference over solid fronted cases.

Running a 2+1 140mm fan setup here in an old fractal design R4 (fans are on a dc controller built into the case, I flick between 5v and 7v depending on use)
Ryzen 7 (fortis malik custom) never been above 60c on full load stress testing, GPU (sapphire pulse rx 580) has never been above 70c.

Thats absolute proof that more fans isn't necessary imo, I have low ambient temps (think 21-26c) but those results are still outstanding irregardless.
 
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