Question Noctua case fans

Feb 10, 2021
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I have the Lian Li 011d XL case and i want to get better fans to mount on the bottom to improve my GPU cooling. From my research i found that the Noctuas are the best you can get for performance but which ones should i get? The ones optimised for airflow or static pressure?
 

Phaaze88

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The more obstacles present, and the more difficult they are, the more the SP fans will pull ahead.
At the same time, the faster you need to run the fans to bring more reasonable volumes of air in.

When obstacles are few and light, the airflow fans tend to do better.

The obstacles around the bottom of the O11 XL are:
-air filter(light)
-distance between the fans placed down there and the surface the chassis is sitting on(heavy)
-the shape of the grille holes that allow air through(medium?)
-hanging/dangling cables(light)

The gpu's fans already act as a bottom intake and have more breathing room available to them compared to fans placed down there.
 
Reactions: Syn89
Feb 10, 2021
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Generally speaking, fans for case are of high airflow type.

Can you justify the use of static pressure fans in this position?
Was thinking the static pressure fans have a more directional airflow to guide to the GPU
 
Feb 10, 2021
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The more obstacles present, and the more difficult they are, the more the SP fans will pull ahead.
At the same time, the faster you need to run the fans to bring more reasonable volumes of air in.

When obstacles are few and light, the airflow fans tend to do better.

The obstacles around the bottom of the O11 XL are:
-air filter(light)
-distance between the fans placed down there and the surface the chassis is sitting on(heavy)
-the shape of the grille holes that allow air through(medium?)
-hanging/dangling cables(light)

The gpu's fans already act as a bottom intake and have more breathing room available to them compared to fans placed down there.
So then i should go for....?
 

Phaaze88

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So then i should go for....?
Nothing really. The gpu's fans are the most effective bottom intake fans.
-they are further away from the 'floor' and thus have more breathing room(won't have to work as hard) compared to fans you're thinking of placing down there
-they already draw air from the bottom, front the side, and the rear PCIe slots

Bottom intake fans don't do as much as you think they would, unless you're ok with the idea of running some at 1300rpm+ and making them the loudest parts in the PC...
And even then, they'd also potentially disrupt rear and side air intake, thus reducing cooling efficiency.

In this scenario I prefer high airflow fans to move as much air as possible to the GPU fan.
They typically have low static pressure, which makes them even weaker in the face of strong obstacles.
Great for exhausts, or front mesh intakes where HDD cages are optional.
 
Feb 10, 2021
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In this scenario I prefer high airflow fans to move as much air as possible to the GPU fan.
Thanks. The reasons i had doubts was because the fans being on the bottom of the case there isn't really big gap between the case and the floor, so it might be a bit difficult to get a lot of air inside the case, and i thought the static pressure fans might have more force tu pull air.
 

lvt

Prominent
Apr 19, 2021
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Thanks. The reasons i had doubts was because the fans being on the bottom of the case there isn't really big gap between the case and the floor, so it might be a bit difficult to get a lot of air inside the case, and i thought the static pressure fans might have more force tu pull air.
You can try both SP and AF fans and pay attention about the noise, due to the design of the blades the noise level may vary. You should keep the ones that make less noise.
 
Feb 10, 2021
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Nothing really. The gpu's fans are the most effective bottom intake fans.
-they are further away from the 'floor' and thus have more breathing room(won't have to work as hard) compared to fans you're thinking of placing down there
-they already draw air from the bottom, front the side, and the rear PCIe slots

Bottom intake fans don't do as much as you think they would, unless you're ok with the idea of running some at 1300rpm+ and making them the loudest parts in the PC...
And even then, they'd also potentially disrupt rear and side air intake, thus reducing cooling efficiency.


They typically have low static pressure, which makes them even weaker in the face of strong obstacles.
Great for exhausts, or front mesh intakes where HDD cages are optional.
So you're saying no fans is better than having extra fans to bring more air to the GPU and inside the case? 🤔
 

Phaaze88

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So you're saying no fans is better than having extra fans to bring more air to the GPU and inside the case? 🤔
To even make that worthwhile, you have to run the fans at high rpms = more noise.
The fans need enough force to overcome the heavy air restriction down there plus bring in air volume - and that means cranking them up, which means more noise, and some folks are picky about noise as it is.

It isn't 'no fans'. The gpu has fans - don't underestimate them.
 
Feb 10, 2021
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To even make that worthwhile, you have to run the fans at high rpms = more noise.
The fans need enough force to overcome the heavy air restriction down there plus bring in air volume - and that means cranking them up, which means more noise, and some folks are picky about noise as it is.

It isn't 'no fans'. The gpu has fans - don't underestimate them.
I understand what you say...but if you really wanted fans down there, what would you pick? Static pressure or airflow?
 

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