Extreme Positive Pressure

[AeroXero]

What would the negative effects be of extreme positive air pressure be? Say 5 intake fans in a case with 1 rear fan w/ a radiator

[Codyman125]

the fans would be fighting each other, meaning that they won't be doing much work

[Si3Rra_7]

5 minutes ago, Codyman125 said:

the fans would be fighting each other, meaning that they won't be doing much work

hmm, i don't agree . diminishing returns would kick in after 3 intake fans but depending on positioning of the fans it would be ok

[ryanmmax]

Name just 1 positive to "extreme"...  Hint there is only one reason, and that it will "maximize" the airflow through the Rad.  Reality is that its more or less negligible and that EVERYTHING else will suffer

 

 

[Tmt97]

15 minutes ago, ryanmmax said:

Name just 1 positive to "extreme"...  Hint there is only one reason, and that it will "maximize" the airflow through the Rad.  Reality is that its more or less negligible and that EVERYTHING else will suffer

 

 

what exactly will be suffering? Ill admit that extreme wont be adding any extra benefit, but I don't see it as hurting anything other than just being a bit wasteful.

[BenjaminC]

Just now, Tmt97 said:

what exactly will be suffering? Ill admit that extreme wont be adding any extra benefit, but I don't see it as hurting anything other than just being a bit wasteful.

Could damage your fans' motors

[W-L]

16 minutes ago, AeroXero said:

What would the negative effects be of extreme positive air pressure be? Say 5 intake fans in a case with 1 rear fan w/ a radiator

Your case will have a limiting factor basically since your trying to force more air into a closed space when only one fan can exhaust. It's better to have a balance where it's just slightly positive airflow preventing dust as long as all intakes are filtered.

[Tmt97]

12 minutes ago, BenjaminC said:

Could damage your fans' motors

Maybe you could wear it out over time if you had it spinning at max speed. But that's true with any air pressure.

[brandishwar]

5 minutes ago, Tmt97 said:

what exactly will be suffering? Ill admit that extreme wont be adding any extra benefit, but I don't see it as hurting anything other than just being a bit wasteful.

A lot of server/rack chassis operate on "extreme positive pressure" by having only intakes on the front with no exhaust. And a lot of rack chassis also have only exhaust fans in the back and no intakes in the front -- these tend to be low profile chassis where the front is filled with hot-swap drive bays.

[Tmt97]

1 hour ago, brandishwar said:

A lot of server/rack chassis operate on "extreme positive pressure" by having only intakes on the front with no exhaust. And a lot of rack chassis also have only exhaust fans in the back and no intakes in the front -- these tend to be low profile chassis where the front is filled with hot-swap drive bays.

Judging by the fact that the op referenced a watercooling radiator in his example, I'm gonna guess that were not discussing server chassis environments. While what you said may be very true in those situations, I don't think it's really relevant to the op unless hes trying to pull off some sort of rackmount gaming PC build like Linus(which would be pretty cool actually).

[HelplmChoking]

Server machines have passive exhaust, while extreme positive pressure is certainly bad for your cooling.
Your fans are having to work hard to push air into your system, pushing against the air that is already in there with nowhere to go, sort of like when you try to slam a door in a small room with closed windows. The only positive would be a little less dust if your intakes are filtered, but no better than having slightly positive pressure.

[dfsdfgfkjsefoiqzemnd]

Positive pressure isn't really a problem as long as you don't overdo it.

A PC case isn't a hermetically sealed environment, so it's not like the air has nowhere to go.  There are plenty of ventilation holes in the back of most cases and all kinds of nooks and crannies all around for air to escape out of.  More positive pressure means that up until some point the air will simply escape through those holes at a higher rate of speed.

 

Sure, it isn't the most effective configuration and at some point you will run into issues.  Based on BeQuiet's specifications, my own rig has a theoretical 250cfm intake and 180cfm exhaust (rough figures, not going to calculate decimals).  If I were to turn around all my exhaust fans so I'd have 8 intakes, I would suck in so much air that I'd lose a lot of the efficiency whilst having wind noise around the ventilation holes.

 

In your case ... well ... I'm not familiar with your exact setup so it's hard to judge.  If you're using some HAF-style case with lots of mesh and openings, it may very well be no issue at all.  If it's something with severe airflow restrictions, it may be an issue.  It's just not possible to tell.  Given the 6 fans you are mentioning (5 in, single rad as exhaust), I'd say "4 in, 1 rad and 1 normal fan as exhaust" is most likely a better option.  Another option might be "1 rad and 3 normal fans in, 2 fans out".  Rad as intake or exhaust doesn't really make a difference in terms of overall temperature.

[LogicalDrm]

There are cases which support all fans positive. Like old Antec LanBoy Air. I wouldn't go full positive with normal steel case with only few passive vents. Your case needs to have someplace for hot air to go.