Looking to attach a Noctua brand 120mm fan to a Noctua NH-D15s, which one is the best option?

[ProtoflareX]

As mentioned in the thread title, I am planning to attach a Noctua brand 120mm fan to the Noctua NH-D15s CPU cooler, which only comes with one fan. If you're wondering why I don't just buy the NH-D15, it's because of RAM clearance issues. Now, with that out of the way, Noctua has an array of 120mm fans available on their product page; however, I am not sure which one is the best choice to attach to the NH-D15s, or if they are even all compatible with it. Based on the statistics that are immediately visible on the product page, it seems as though either the:

 

Noctua NF-A12x25 PWM

 

or

 

NF-S12A PWM

 

would be the best picks. Of course, I may be wrong about that. Would anyone be willing to help me determine which Noctua brand 120mm fans are compatible with the NH-D15s and which of those compatible fans would maximize cooling performance?

[Jurrunio]

What case is this and how much RAM clearance do you need? Because Noctua's fan clip design means you can easily raise the front fan by another 30mm from stock as long the side panel of the case don't get in the way. Yes, that's NH-D15 with the stock NF-A15

[ProtoflareX]

5 minutes ago, Jurrunio said:

What case is this and how much RAM clearance do you need? Because Noctua's fan clip design means you can easily raise the front fan by another 30mm from stock as long the side panel of the case don't get in the way. Yes, that's NH-D15 with the stock NF-A153

It's a Cooler Master H500, which has a CPU cooler clearance of 167mm. The NH-D15 is 165mm tall, allowing me only 2mm of space to move its 140mm fans, so that's definitely out of the question. That's the reason I have to look into a 120mm fan to attach to it.

[Jurrunio]

5 minutes ago, ProtoflareX said:

It's a Cooler Master H500, which has a CPU cooler clearance of 167mm. The NH-D15 is 165mm tall, allowing me only 2mm of space to move its 140mm fans, so that's definitely out of the question. That's the reason I have to look into a 120mm fan to attach to it.

then the NF-F12 is the best from Noctua, closely followed by the NF-A12x25. Static pressure here is more important than airflow rate (even though both are necessary). S12 has weak static pressure in comparison, so no.

 

I'm not sure if they give you fan clips, you might end up using cable ties if they don't.

[ProtoflareX]

1 minute ago, Jurrunio said:

then the NF-F12 is the best from Noctua, closely followed by the NF-A12x25. Static pressure here is more important than airflow rate (even though both are necessary).

Interesting, why exactly is that?

[WoodenMarker]

6 minutes ago, ProtoflareX said:

It's a Cooler Master H500, which has a CPU cooler clearance of 167mm. The NH-D15 is 165mm tall, allowing me only 2mm of space to move its 140mm fans, so that's definitely out of the question.

What ram are you using? 

3 minutes ago, Jurrunio said:

then the NF-F12 is the best from Noctua, closely followed by the NF-A12x25. Static pressure here is more important than airflow rate (even though both are necessary).

Neither static pressure nor airflow is more important than the other. What's considered high static pressure or airflow is relative.

The NF-F12 is not better in this case. The NF-A12x25 has a better balance of static pressure and airflow and it's why Noctua's new coolers are using the NF-A12x25 instead of the NF-F12. Its real-world performance is generally better than either the NF-F12 or NF-S12A: https://noctua.at/en/nf-a12x25-performance-comparison-to-nf-f12-and-nf-s12a

 

Here's an example on the similar NH-U12S heatsink: https://www.eteknix.com/noctua-fans-super-test-which-ones-are-right-for-you/4/

on a H5 heatsink: https://www.hardwareluxx.de/index.php/artikel/hardware/kuehlung/46712-noctua-nf-a12x25-im-test-auf-dem-weg-zur-luefter-referenz.html?start=4

on a GeminII heatsink: http://www.comptoir-hardware.com/articles/refroidissement/36673-nous-avons-essaye-les-noctua-nf-a12x25.html?start=2

on 30 / 50mm rads and a high restriction simulation: https://www.thelab.gr/reviews/heatsinks-coolers-watercooling-reviews/noctua-nf-a12x25-and-noctua-nf-p12-redux-series-fans-review-r701/

You'd be hard pressed to find examples of the NF-F12 performing better outside of higher rpm examples like the iPPC line. Even then, the NF-A12x25 performs much better for the noise. Example on a DRTF: https://www.enlacehw.com/noctua-nf-a12x25-review/3/

 

That being said, it's probably still better to go with a NF-A15 if possible since it seems to perform better here on the dual tower NH-D14: https://youtu.be/eBXT_dLoQtA

[ProtoflareX]

12 minutes ago, WoodenMarker said:

What ram are you using? 

 

...it's probably still better to go with a NF-A15 if possible since it seems to perform better here on the dual tower NH-D14: https://youtu.be/eBXT_dLoQtA

I'm going to be using G.Skill Flare X 3200MHz RAM, which is 40mm tall. Also, your post has left me with two questions:

 

1. If static pressure and airflow are equally as important as each other, then is the NF-A12x25, which balances both, better than the NF-F12 and NF-S12A in all situations? 

 

2. I noticed that you recommended the NF-A15 toward the end of your post. You're referring to the 140mm fan, correct? If that's the case, then unfortunately that option is out, as my case doesn't accommodate raising a 140mm fan such that there is enough clearance for 40mm tall RAM. I'm guessing I should go with the NF-A12x25?

[WoodenMarker]

1 minute ago, ProtoflareX said:

I'm going to be using G.Skill Flare X 3200MHz RAM, which is 40mm tall. Also, your post has left me with two questions:

1. If static pressure and airflow are equally as important as each other, then is the NF-A12x25, which balances both, better than the NF-F12 and NF-S12A in all situations? 

2. I noticed that you recommended the NF-A15 toward the end of your post. You're referring to the 140mm fan, correct? If that's the case, then unfortunately that option is out, as my case doesn't accommodate raising a 140mm fan such that there is enough clearance for 40mm tall RAM. I'm guessing I should go with the NF-A12x25?

The optimal fan provides as much airflow as possible and enough static pressure for where it's being used. A fan with no airflow provides no cooling. Since every use case requires some static pressure, a fan with no static pressure would also provide no cooling. Static pressure and airflow are two sides of the same coin. 

The NF-A12x25 is better than NF-F12 and NF-S12A in most situations but not all. The article on Noctua's website shows the relationship between the 3 fans in different situations. 

Yes, I'm referring to the 140mm fan. The fan in the default position makes the cooler 160mm tall and allows for 32mm of clearance for ram. In the H500 case, it can be raised 7mm for 39mm of clearance. That might be enough for the 40mm tall Flare X if there's enough leeway in the case cooler clearance. There's usually more headroom than case specs would suggest but I'm not sure if it would enough for an extra 1mm. 

[ProtoflareX]

4 minutes ago, WoodenMarker said:

Yes, I'm referring to the 140mm fan. The fan in the default position makes the cooler 160mm tall and allows for 32mm of clearance for ram. In the H500 case, it can be raised 7mm for 39mm of clearance. That might be enough for the 40mm tall Flare X if there's enough leeway in the case cooler clearance. There's usually more headroom than case specs would suggest but I'm not sure if it would enough for an extra 1mm. 

That sounds a little too close for comfort in my opinion. In order to completely eliminate the chance of potential incompatibility, I'd rather play it safe with a 120mm fan, namely the NF-A12x25.

[_Hustler_One_]

I experimented my NH-D15 to be using my spare NF-F12 and NF-A14 and took off the original fan NF-A15, these 2 fans (F12 & A14) if they're installed on the front they will hang their lower anti-vibration rubber pads, both fans, either the NF-F12 and NF-A14.

 

The NF-F12 still can get all of its rubber pads contact with heatsink if it's installed on the 2nd tower, but not with the NF-A14, this A14 will hang its lower anti-vibration rubber pads on either front and rear heatsink.

 

So keep that in mind..

 

The side effect with the noise is unnoticeable but it will scratch the fan frame if you insist to install it that way. I recommend to stay with the NF-A15 because its anti-vibration rubber pads position on the fan frame are optimized for the design of the heatsink profile, and leave the front tower empty without fan, use a single NF-A15 instead of adding any 120mm fan, the performance difference is minimal between 1 vs 2 fans NH-D15/S.