[SOLVED] Questions about case fan speeds & airflow

Aug 28, 2019
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Hi everyone.
I have a build that I hope to get soon and I have some questions about my case airflow.


Here are my specs:
MB: Asus TUF GAMING X570-PLUS
CPU: AMD Ryzen 9 3900x
AIO: NZXT Kraken X62
GPU: Gigabyte RTX 2080 SUPER 8GB GAMING OC
Case: NZXT H700i


I know the H700i comes with 3 front intake fans (all 120mm) and 1 exhaust fan on the back (140mm),
I am hoping to top mount the X62 and use both of its 140mm fans as exhausts.
Will that create negative pressure inside the case?
If so, how should I change my fan configuration and/or fan speeds to make it maybe positive pressured?


Also here are the fan specs:

Three fans in the front are:
Aer F120 (Case Version)
Speed: 1200 + 200 RPM
Airflow: 50.42 CFM

The back fan is:
Aer F140 (Case Version)
Speed: 1,000 + 200 RPM
Airflow: 68.95 CFM

The AIO's fans are:
Aer P140
Speed: 500~1,800 +/- 300RPM
 

Darkbreeze

Titan
Moderator
Negative pressure NORMALLY equals better cooling performance, if the configuration is negative pressure AND has sufficient airflow through the case. Obviously, having only one fan, in the rear location, is going to create a negative pressure situation but isn't going to offer enough airflow for the majority of gaming or enthusiast builds, so the pressure arrangement is only arguable if we can assume that it is a given pressure differential AND has enough CFM/Airflow through the case to provide decent movement and exchange to leverage the stack effect.

If you don't know what stack effect is, it would help to read this:

https://www.energyvanguard.com/blog/50616/Heat-Rises-and-Falls-Stack-Effect-Air-Movement-Heat-Flow

Neutral pressure is generally the sweet spot with a balance of good cooling performance and some dust suppression.

Positive pressure tends to have somewhat less cooling performance, but offers good dust suppression, but if there is sufficient exhaust flow and there is still positive pressure due to the arrangement and number of fans, then it can still have pretty good cooling performance.

Radiators offer somewhat better cooling performance if they are installed in an intake orientation, because they are using the nominally cooler outside ambient air to cool with rather than trying to use already heated internal case air. The amount of heat that is removed into the case from the radiator when using it in an intake configuration is barely measurable, so there is little to no negative impact on other components in the case, ESPECIALLY if you have plenty of exhaust fans installed to ensure a rapid exchange of airflow through the case.

It is advisable for MOST configurations to use the radiator in an intake configuration whenever possible. Obviously using one in an exhaust configuration in the top of the case is an option as well but from what I've seen you can expect a couple of degrees difference between using one in an intake or in an exhaust configuration. I recommend mounting it in front as an intake setup when possible.

I would move the other fans to the top as exhaust, so that you will have one rear exhaust, one top rear exhaust and one middle top exhaust. Radiator in front with the fans it came with.
 
Reactions: AdmiralDonut

Darkbreeze

Titan
Moderator
Negative pressure NORMALLY equals better cooling performance, if the configuration is negative pressure AND has sufficient airflow through the case. Obviously, having only one fan, in the rear location, is going to create a negative pressure situation but isn't going to offer enough airflow for the majority of gaming or enthusiast builds, so the pressure arrangement is only arguable if we can assume that it is a given pressure differential AND has enough CFM/Airflow through the case to provide decent movement and exchange to leverage the stack effect.

If you don't know what stack effect is, it would help to read this:

https://www.energyvanguard.com/blog/50616/Heat-Rises-and-Falls-Stack-Effect-Air-Movement-Heat-Flow

Neutral pressure is generally the sweet spot with a balance of good cooling performance and some dust suppression.

Positive pressure tends to have somewhat less cooling performance, but offers good dust suppression, but if there is sufficient exhaust flow and there is still positive pressure due to the arrangement and number of fans, then it can still have pretty good cooling performance.

Radiators offer somewhat better cooling performance if they are installed in an intake orientation, because they are using the nominally cooler outside ambient air to cool with rather than trying to use already heated internal case air. The amount of heat that is removed into the case from the radiator when using it in an intake configuration is barely measurable, so there is little to no negative impact on other components in the case, ESPECIALLY if you have plenty of exhaust fans installed to ensure a rapid exchange of airflow through the case.

It is advisable for MOST configurations to use the radiator in an intake configuration whenever possible. Obviously using one in an exhaust configuration in the top of the case is an option as well but from what I've seen you can expect a couple of degrees difference between using one in an intake or in an exhaust configuration. I recommend mounting it in front as an intake setup when possible.

I would move the other fans to the top as exhaust, so that you will have one rear exhaust, one top rear exhaust and one middle top exhaust. Radiator in front with the fans it came with.
 
Reactions: AdmiralDonut

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