Is Neg air pressure really that bad?

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42 minutes ago, Xdrone said:

Alright everyone needs to calm down ? 

I appreciate the solid discussions, but I have come to a conclusion after analysing all this information I have received, I will keep it balanced, and get 6 ml120 fans all of which cover the intake and outtake (3 each).

Thankyou guys for helping me reach this conclusion. 

I think we are calm  Just trying to set the facts straight

[LogicalDrm]

8 hours ago, Ryan_Vickers said:

I think we are calm  Just trying to set the facts straight

Which is good thing. As I've seem to have fallen same trap as those still claiming "hot air rising" (I know I'm bringing it back, but its hilarious misconception) has some real effect in PC component cooling. Now I've been corrected on pressure thing. Which has fallen into same answer with "push vs pull" "which RAM" and "Whats best Gaming mobo/RAM". Aka doesn't matter. Except for those with dust phobia.

[HisEvilness]

I am sorry but hot air does rise and negative pressure helps it rise faster due to the excess exhaust, while not being a vacuum since air will try to enter the case to make up for the pressure difference.

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1 hour ago, HisEvilness said:

I am sorry but hot air does rise and negative pressure helps it rise faster due to the excess exhaust, while not being a vacuum since air will try to enter the case to make up for the pressure difference.

Since hot air rising is at least an actual phenomenon and because I don't have any test data to validate one way or the other, I can't claim anything with absolute certainty, but I feel very strongly that it most likely has little if any noticeable effect.  I suspect that the amount of air movement in a case caused by the fans in all likelihood is orders of magnitude more significant than the free convection caused by hot air rising.  For evidence I would point you to the following experiment: place your hand above a hot stove and take note of how much air you feel raising up from it.  I suspect the answer will be "none" or close to it, and that's a heat source massively hotter than the air than a PC component would be, so if you can't feel it there you know with certainty that the effect will be probably a good 10x weaker coming off a heatsink.  Then place your hand above a fan mounted to move air upward at the same distance away.  I think you'll find the fan creates a much more noticeable stream of air.

[HisEvilness]

28 minutes ago, Ryan_Vickers said:

Since hot air rising is at least an actual phenomenon and because I don't have any test data to validate one way or the other, I can't claim anything with absolute certainty, but I feel very strongly that it most likely has little if any noticeable effect.  I suspect that the amount of air movement in a case caused by the fans in all likelihood is orders of magnitude more significant than the free convection caused by hot air rising.  For evidence I would point you to the following experiment: place your hand above a hot stove and take note of how much air you feel raising up from it.  I suspect the answer will be "none" or close to it, and that's a heat source massively hotter than the air than a PC component would be, so if you can't feel it there you know with certainty that the effect will be probably a good 10x weaker coming off a heatsink.  Then place your hand above a fan mounted to move air upward at the same distance away.  I think you'll find the fan creates a much more noticeable stream of air.

Well I've held my hand on a hot plate so i know how that feels lol when i was a kid that is.
But when I for instance run Prime95 the rad of the AIO does dissipate heat with push pull, having a greater effect when i added the pull fans.
Temps are lower as well of the HWiNFO with push and pull over just push that does give a measurable result speaking for increased air flow

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1 hour ago, HisEvilness said:

Well I've held my hand on a hot plate so i know how that feels lol when i was a kid that is.
But when I for instance run Prime95 the rad of the AIO does dissipate heat with push pull, having a greater effect when i added the pull fans.
Temps are lower as well of the HWiNFO with push and pull over just push that does give a measurable result speaking for increased air flow

I'm not sure what any of this has to do with what I said...

[Mira Yurizaki]

Ah fun, airflow and stuff. I usually don't think about this too much because I think there's too much overthinking on this subject. And here's why (omg clickbait title material right here)

• Anything that needs forced convection has a fan and it's more than likely going to be blowing air faster than any airflow reaching the part from the case fans, contributing to way more cooling than any airflow in the case. Unless you have case fans that are already blowing hurricanes inside.
• Natural convection accounts for very little airflow and is probably given more concern than necessary considering actively cooled parts are usually in an airflow path anyway. If anything, cooler air should come from the top so that it falls down and naturally circulates the temperature within.
• Ultimately: as long as there's air circulation through the parts that need to be cooled, it doesn't really matter. My case may seem sketchy with cooling, considering how cramped it is, but my video card can easily maintain speeds above advertised boost clocks and my CPU can maintain turbo speeds just fine, simply because there's enough ventilation in the case to move air in and out.

I don't advocate negative air pressure if only because of the potential for increased dust intake in nooks and crannies of the system.

[airdeano]

wise, choice, but remember; air filters will reduce the amount of airflow (about 50%) so your 3 and 3 idea  is more like 1.5 in and 3 out (negative pressure). to equalize, the front fans will have to be at 100% and the exhaust will have to be at 50% fan speeds. some of that untold mojo/sciencey stuff.

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14 minutes ago, airdeano said:

wise, choice, but remember; air filters will reduce the amount of airflow (about 50%) so your 3 and 3 idea  is more like 1.5 in and 3 out (negative pressure). to equalize, the front fans will have to be at 100% and the exhaust will have to be at 50% fan speeds. some of that untold mojo/sciencey stuff.

Yes of course when trying to consider how your airflow is balanced, you need to consider the specs of the fan (static pressure, airflow values), as well as any obstructions (rads, filters, etc.) and at the end of the day, you probably won't be able to calculate or estimate any of that particularly accurately so if you really want to go for positive or negative, make sure you get larger and/or more fans and run them faster for either the intake or exhaust (again, depending what you're going for).

[Xdrone]

4 hours ago, airdeano said:

wise, choice, but remember; air filters will reduce the amount of airflow (about 50%) so your 3 and 3 idea  is more like 1.5 in and 3 out (negative pressure). to equalize, the front fans will have to be at 100% and the exhaust will have to be at 50% fan speeds. some of that untold mojo/sciencey stuff.

I am aware of this, the fans will be but at higher rpms for stronger pressure pull through the rad, which will be mounted at the top.

[LogicalDrm]

On 8/15/2017 at 6:59 PM, HisEvilness said:

I am sorry but hot air does rise and negative pressure helps it rise faster due to the excess exhaust, while not being a vacuum since air will try to enter the case to make up for the pressure difference.

 

My favorite PC air cooling myth. Or actually its not myth, but common misconception about that it would make any difference. Hot air rising is physical fact. Lets leave that be. Main but comes from when it happens. Answer being everywhere. I don't have numbers on how fast convection would work and how big of temp difference needs to be for it to make any sense. But since temp difference between air above/around hot components and overall in case isn't that big, any external force moving air eliminates its meaning in such small space as PC case. Inside the case fans move air, not natural convection. In whole room its different thing, where floor is colder than table or roof.

 

On 8/15/2017 at 9:07 PM, HisEvilness said:

Well I've held my hand on a hot plate so i know how that feels lol when i was a kid that is.
But when I for instance run Prime95 the rad of the AIO does dissipate heat with push pull, having a greater effect when i added the pull fans.
Temps are lower as well of the HWiNFO with push and pull over just push that does give a measurable result speaking for increased air flow

 

I hope you have better temp sensors to use for testing. Your hand is most inaccurate thing you can use. Human body temp is 34-37C. Anything hotter than that feels hot. Anything cooler feels cold. You can't make any accurate estimation on temps based on feeling something.