3 120 airflow fans IN vs 6 120 static pressure fans (on rads) OUT = ?

[Xeliath]

Question: 3 NF-S12A's in vs 6 NF-F12's out = positive or negative air pressure

What I am asking is, if I had 3 NF-S12A's (Airflow optimized fans) blowing in my case, and six NF-F12's mounted on radiators blowing out, would it result in positive or negative air pressure.

Random: This should make no difference: the fans are all going to be from Noctua's Chromax lineup.

 

Reason: Because people seem to want a reason, I am planning a PC-O11 Dynamic build, and I plan on having two 360MM radiators with NF-F12's, and I would like to know if 3 NF-S12A's would be enough (on the bottom) to create positive air pressure inside the case

 

No big deal if it isn't, this is mostly out of curiosity.

Also, is this the right category to post this under?

[Master Disaster]

3 in 6 out, assuming they're identical, will give you negative pressure as more air is being expelled than sucked in.

 

Can we also clarity, negative pressure is impossible, what we really mean is below ambient pressure.

[Xeliath]

1 hour ago, Master Disaster said:

3 in 6 out, assuming they're identical, will give you negative pressure as more air is being expelled than sucked in.

 

Can we also clarity, negative pressure is impossible, what we really mean is below ambient pressure.

This is what I am asking, with 3 airflow focused fans in, and 6 static pressure focused fans mounted on radiators out, would it end up with positive or negative air pressure

[WoodenMarker]

Maintaining positive pressure is generally just a matter of running your intakes at higher rpm than your exhausts. 

The bottom of the PC-011 isn't very open and not far from the surface you place the case unless you elevate it further with some sort of stand beneath the feet. I would recommend getting fans that are more optimized for static pressure than the NF-S12A's. If you can afford spending a bit more, NF-A12x25's would be better and are about as good as it gets for 120mm fans. 

[Xeliath]

9 hours ago, WoodenMarker said:

Maintaining positive pressure is generally just a matter of running your intakes at higher rpm than your exhausts. 

The bottom of the PC-011 isn't very open and not far from the surface you place the case unless you elevate it further with some sort of stand beneath the feet. I would recommend getting fans that are more optimized for static pressure than the NF-S12A's. If you can afford spending a bit more, NF-A12x25's would be better and are about as good as it gets for 120mm fans. 

Okay, but since six of the fans are going to be mounted on EK's slim triple 120mm radiators, how of a dfference would that make?
NF-A12x25's aren't actually that much more, just about $5 more per fan. This isn't really a budget build
Current design (Haven't ordered the parts yet, probably won't until I get some IRL things sorted)
i9 9900KF

TridentZ RGB 2x16GB DDR4-3200 C14
Nvidia RTX 2080 Ti (FE)
Asus ROG Maximus XI Apex
Samsung 970 Evo Plus 2TB
Seagate Exos X6 6TB HDD (Just don't ask... I don't know...)
Lian Li PC-O11 Dynamic
Seasonic Prime 1000 Titanium 1000W 80+ Titanium

3x Noctua NF-A12x25 PWM Chromax
6x Noctua NF-F12 PWM Chromax

EK-CoolStream 360 SE Slim

IDK which, but I will get custom sleeved cables from CableMod, unless there are better ones out there.

All (other) the water cooling components will be from EKWB. Specific parts TBD

Haven't decided on anything else yet

[WoodenMarker]

2 hours ago, Xeliath said:

Okay, but since six of the fans are going to be mounted on EK's slim triple 120mm radiators, how of a dfference would that make?
NF-A12x25's aren't actually that much more, just about $5 more per fan. This isn't really a budget build
Current design (Haven't ordered the parts yet, probably won't until I get some IRL things sorted)

3x Noctua NF-A12x25 PWM Chromax

It's hard to tell how much of a difference it would make without just testing it which is what I'd recommend doing. You can use incense sticks to test where air is being drawn in and exhausted to see if there are any unfiltered leaks. 

A lazier approach that should still work is to just run your intakes at higher rpm than your exhausts. Double the rpm for the intakes should work pretty well. 

 

The Chromax NF-A12x25's are on the roadmap for the first half of 2020 but don't be surprised if there are delays. If you need black fans sooner, you can just use NF-F12's instead,