Two 140mm fans or one 200mm fan for a top of case exhaust fan?

[ProtoflareX]

I am going to be purchasing a Cooler Master H500 Case soon, which comes with three fans by default; two 200mm intake fans on its front and one 120mm exhaust fan in the back. The case also supports either two 140mm fans or one 200mm fan on its top. In order to maximize airflow, I wish to purchase a fan (or possibly fans) to serve as an exhaust fan slot in the top. However, I need help determining if two 140mm fans or one 200mm fan would be better for the job. Ideally, I would like whichever option will remove greater amounts of hot air from the case at once.

[emosun]

two 140mm fans would move the most air due to surface area if we ignore rpm and fan design

[ProtoflareX]

11 minutes ago, emosun said:

two 140mm fans would move the most air if we ignore rpm and fan design

Oh, I probably should have mentioned what fans I plan on buying. Ideally, I would buy something from Noctua, such as:

 

One of these two (not sure what the difference is):
First Noctua 200mm
Second Noctua 200mm

 

Or two of one of these (again, not sure what the difference is):

First Noctua 140mm

Second Noctua 140mm

Third Noctua 140mm

 

Does that change anything?

[emosun]

well find the cfm for each fan ad see if two 140s will be more than the single 200

 

[Velcade]

A single 200mm fan will be quieter than two 140mm fans.

[emosun]

1 minute ago, Velcade said:

A single 200mm fan will be quieter than two 140mm fans.

the surface area is higher on two 140mm fans , meaning they can spin slower and move the same amount of air , not that it matters becuase he doesn't care about noise

[ProtoflareX]

43 minutes ago, emosun said:

well find the cfm for each fan ad see if two 140s will be more than the single 200

 

Admittedly, I had to do research on what CFM meant, but I managed to figure it out. So let's say a single Noctua 200mm fan has a CFM of 86.46 and a single Noctua 140mm fan has a CFM of 82.51; that means the single 200mm fan moves slightly more air than the 140mm fan, but two 140mm fans have a CFM of 165.02, meaning they move nearly twice the amount of air that the single 200mm fan moves?

 

 

[emosun]

 

46 minutes ago, ProtoflareX said:

So let's say a single Noctua 200mm fan has a CFM of 86.46 and a single Noctua 140mm fan has a CFM of 82.51; that means the single 200mm fan moves slightly more air than the 140mm fan, but two 140mm fans have a CFM of 165.02, meaning they move nearly twice the amount of air that the single 200mm fan moves?

yep, if you just want to move a lot of air then 165 is definitely more than  82

[Kryptyle]

2 hours ago, ProtoflareX said:

Oh, I probably should have mentioned what fans I plan on buying. Ideally, I would buy something from Noctua, such as:

 

One of these two (not sure what the difference is):
First Noctua 200mm
Second Noctua 200mm

 

Or two of one of these (again, not sure what the difference is):

First Noctua 140mm

Second Noctua 140mm

Third Noctua 140mm

 

Does that change anything?

One of the 200mm fans you posted is PWM or - Pulse Width Modulated. This means it can be controlled in software by either the CPU_FAN header or any other Header on the motherboard that allows PWM control. This allows for more granular fan curves if you want to really tune when your fans kick in for better control over acoustics.

 

One of the 140mm fans you have is also PWM. The other is ULN which is Noctua's branding for a lower noise fan that has lower max RPMs to reduce noise. I wouldn't suggest getting this one since you can get a similar effect by using the 'Low Noise Adapter' that Noctua includes with their fans.

 

The third 140 mm fan is an FLX and looks like a DC controlled fan (Non-PWM) and has specific RPM steps for DC control if your motherboard doesn't have any extra PWM headers or you have a non-pwm fan controller.

 

Having gone over all of that, go for the two 140s, you'll have better airflow since they have higher combined CFM, 200 mm fans have a lot of compatibility issues as well. As to which fan, go with the PWM 140mm, Noctua fans last forever, you can reuse it and even if you don't need PWM now, you'll get use out of it later.

 

And you can connect PWM fans to Non-PWM headers, you just won't get the fan control but the fan will spin and blow just fine.

[ProtoflareX]

17 minutes ago, Kryptyle said:

One of the 200mm fans you posted is PWM or - Pulse Width Modulated. This means it can be controlled in software by either the CPU_FAN header or any other Header on the motherboard that allows PWM control. This allows for more granular fan curves if you want to really tune when your fans kick in for better control over acoustics.

 

One of the 140mm fans you have is also PWM. The other is ULN which is Noctua's branding for a lower noise fan that has lower max RPMs to reduce noise. I wouldn't suggest getting this one since you can get a similar effect by using the 'Low Noise Adapter' that Noctua includes with their fans.

 

The third 140 mm fan is an FLX and looks like a DC controlled fan (Non-PWM) and has specific RPM steps for DC control if your motherboard doesn't have any extra PWM headers or you have a non-pwm fan controller.

 

Having gone over all of that, go for the two 140s, you'll have better airflow since they have higher combined CFM, 200 mm fans have a lot of compatibility issues as well. As to which fan, go with the PWM 140mm, Noctua fans last forever, you can reuse it and even if you don't need PWM now, you'll get use out of it later.

 

And you can connect PWM fans to Non-PWM headers, you just won't get the fan control but the fan will spin and blow just fine.

Thanks for the extremely informative reply, especially when it comes to explaining what PWM meant. In the interim between my last post and this one, I did a bit of research on the best possible options for 140mm fans to install into the case's top slots and actually decided that one of the two fans linked below would be better options than any of the three 140mm fans I linked earlier.

 

140mm Fan #1

140mm Fan #2

 

However, I'm not quite sure what the difference between the two of them is. As far as I can tell, they are both PWM fans, meaning I should be able to adjust them, but beyond that I'm not tech savvy enough to identify the differences between them using just the spec sheet. Any chance you could elucidate this for me?

[Kryptyle]

3 minutes ago, ProtoflareX said:

Thanks for the extremely informative reply, especially when it comes to explaining what PWM meant. In the interim between my last post and this one, I did a bit of research on the best possible options for 140mm fans to install into the case's top slots and actually decided that one of the two fans linked below would be better options than any of the three 140mm fans I linked earlier.

 

140mm Fan #1

140mm Fan #2

 

However, I'm not quite sure what the difference between the two of them is. As far as I can tell, they are both PWM fans, meaning I should be able to adjust them, but beyond that I'm not tech savvy enough to identify the differences between them using just the spec sheet. Any chance you could elucidate this for me?

No problem, fans can get confusing.

 

Those are Noctua's industrial line, they are build with far superior materials and are more expensive. They run at higher RPMs too and can get quite loud, annoyingly loud in fact.

 

The difference between the two fans is input voltage rating. The first is rated at 12v of input voltage. This is typically what PC fans run at. The second is rated up to 24v, your motherboard is very unlikely to provide that kind of output. I'm not familiar enough with the fans to know what they would do under under-volted conditions. If you had to go with one of these I would suggest the first fan.

 

Having said all of that, I wouldn't recommend going with the industrial PPC fans. They're loud, expensive and a little overkill. They are the best for cooling no-question, but you may not need them. If the only reason you picked them instead of the regular ones is because they are black instead of brown and beige and ugly (Which is a very valid reason, I love Noctua fans but I hate the colors), then there is another option.

 

Check out the Noctua Chromax 140mm fans:

 

Chromax NF-A14

 

The fans are black and they allow you to customize the noise dampening rubber grommets too so you can match them with the rest of your build. Also they aren't as expensive as industrial fans and are much quieter. They are basically better looking regular Noctua Fans.

 

 

 

[ProtoflareX]

12 minutes ago, Kryptyle said:

No problem, fans can get confusing.

 

Those are Noctua's industrial line, they are build with far superior materials and are more expensive. They run at higher RPMs too and can get quite loud, annoyingly loud in fact.

 

The difference between the two fans is input voltage rating. The first is rated at 12v of input voltage. This is typically what PC fans run at. The second is rated up to 24v, your motherboard is very unlikely to provide that kind of output. I'm not familiar enough with the fans to know what they would do under under-volted conditions. If you had to go with one of these I would suggest the first fan.

 

Having said all of that, I wouldn't recommend going with the industrial PPC fans. They're loud, expensive and a little overkill. They are the best for cooling no-question, but you may not need them. If the only reason you picked them instead of the regular ones is because they are black instead of brown and beige and ugly (Which is a very valid reason, I love Noctua fans but I hate the colors), then there is another option.

 

Check out the Noctua Chromax 140mm fans:

 

Chromax NF-A14

 

The fans are black and they allow you to customize the noise dampening rubber grommets too so you can match them with the rest of your build. Also they aren't as expensive as industrial fans and are much quieter. They are basically better looking regular Noctua Fans.

 

 

 

Truth be told, the reason I had my eye on those instead of the previous options is because I recently decided on a Noctua NH-D15 CPU cooler instead of a 360mm liquid cooler as I had originally intended. I am looking to craft a gaming rig that will last many years to come, meaning my plans will be foiled if a pump fails, or if coolant is sprayed all over my hardware. In pursuit of that goal, I am looking for air cooling parts that facilitate medium to "low-high" overclocks while still maintaining acceptable temperatures. Since I am now going with air CPU cooling instead of liquid CPU cooling, I figured that more effort would need to be put in to moderate the temperatures of both the CPU and the case itself; that's why I figured those industrial fans would be the best option. What you said about their noise levels does concern me, though. I'm assuming that a high level of noise would only occur if I were to put my PC under strain with an activity such as intensive gaming, correct?

[Kryptyle]

14 minutes ago, ProtoflareX said:

Truth be told, the reason I had my eye on those instead of the previous options is because I recently decided on a Noctua NH-D15 CPU cooler instead of a 360mm liquid cooler as I had originally intended. I am looking to craft a gaming rig that will last many years to come, meaning my plans will be foiled if a pump fails, or if coolant is sprayed all over my hardware. In pursuit of that goal, I am looking for air cooling parts that facilitate medium to "low-high" overclocks while still maintaining acceptable temperatures. Since I am now going with air CPU cooling instead of liquid CPU cooling, I figured that more effort would need to be put in to moderate the temperatures of both the CPU and the case itself; that's why I figured those industrial fans would be the best option. What you said about their noise levels does concern me, though. I'm assuming that a high level of noise would only occur if I were to put my PC under strain with an activity such as intensive gaming, correct?

Yes exactly, though if you have them on the cooler you would be able to set up fan curves to reduce the RPMs. Though if you're doing that then you're basically downgrading the fans back to the regular fans' RPMs.

 

The NH-D15 is a great tower style air-cooler. In fact, it'll generally let you overclock pretty well too. The cooler comes with two of the NF-A15 140mm fans anyway. Those should be more than enough for overclocking. My suggestion would be to get the cooler and try out how much you can overclock, if you are happy with the results then you wouldn't need the higher power fans anyway. If you have a stable overclock but your temps are too high you can go for the Industrial fans.

 

I think you should be fine with the NH-D15 as is though, what CPU are you planning to cool? I'm not sure if I saw you mention that.

[ProtoflareX]

7 minutes ago, Kryptyle said:

Yes exactly, though if you have them on the cooler you would be able to set up fan curves to reduce the RPMs. Though if you're doing that then you're basically downgrading the fans back to the regular fans' RPMs.

 

The NH-D15 is a great tower style air-cooler. In fact, it'll generally let you overclock pretty well too. The cooler comes with two of the NF-A15 140mm fans anyway. Those should be more than enough for overclocking. My suggestion would be to get the cooler and try out how much you can overclock, if you are happy with the results then you wouldn't need the higher power fans anyway. If you have a stable overclock but your temps are too high you can go for the Industrial fans.

 

I think you should be fine with the NH-D15 as is though, what CPU are you planning to cool? I'm not sure if I saw you mention that.

I'm actually currently choosing parts for a prospective Zen 2 CPU build. Assuming the naming pattern remains consistent, the CPU I intend to get would be the Ryzen 7 3700X, which may finally be revealed tomorrow at CES. By the way, when you said the NH-D15 comes with two NF-A15s, did you mean that it comes with two fans that are meant to be attached to the cooler's fins, or are there fans attached to the fins by default and two extra fans are included in the box for replacement / case usage?

[WoodenMarker]

1 hour ago, ProtoflareX said:

it comes with two fans that are meant to be attached to the cooler's fins

^

[ProtoflareX]

1 minute ago, WoodenMarker said:

^

Thanks for answering my question. I have another one if you don't mind: Is it possible for me to replace the fans on the NH-D15 with different Noctua fans of the same size?

[WoodenMarker]

2 minutes ago, ProtoflareX said:

Thanks for answering my question. I have another one if you don't mind: Is it possible for me to replace the fans on the NH-D15 with different Noctua fans of the same size?

Yes, any fans with standard 120mm mounting holes would fit. This includes 140mm's with a rounded frame like the NF-A15's that already come with it. 

That being said, the included fans are excellent and there isn't much benefit in replacing them. 

[ProtoflareX]

1 minute ago, WoodenMarker said:

Yes, any fans with standard 120mm mounting holes would fit. This includes 140mm's with a rounded frame like the NF-A15's that already come with it. 

That being said, the included fans are excellent and there isn't much benefit in replacing them. 

Ah, I see. So there would be a more noticeable effect on case + CPU temps by replacing stock fans with similarly sized Noctua fans?

[WoodenMarker]

Just now, ProtoflareX said:

Ah, I see. So there would be a more noticeable effect on case + CPU temps by replacing stock fans with similarly sized Noctua fans?

The difference new fans would make depends on how adequate the current cooling is. Once you have enough cooling, you quickly run into diminishing returns and better fans don't make as much of a difference. I'd suggest using just the stock case fans and seeing how they perform before deciding on whether or not to buy new fans. 

 

[ProtoflareX]

1 hour ago, WoodenMarker said:

The difference new fans would make depends on how adequate the current cooling is. Once you have enough cooling, you quickly run into diminishing returns and better fans don't make as much of a difference. I'd suggest using just the stock case fans and seeing how they perform before deciding on whether or not to buy new fans. 

Well the two slots on the top of the case I'm buying are unoccupied by default, so I'm planning on getting something to fill those. That being said, my research on case fans is nearing its conclusion. I think I only have two more questions, which hopefully you can help me with. 

 

For my first question, I would like to know what the difference between the two 120mm models linked below is. The first model claims to have a higher CFM while simultaneously having a lower RPM, but I don't understand how that's possible. Doesn't that make it objectively better than the second one?

120mm Noctua fan #1

120mm Noctua fan #2

 

As for my second question, I would once more like to know what the difference between two fans is, but this time, the question concerns two different 140mm models.
140mm Noctua fan #1

140mm Noctua fan #2

 

 

 

[WoodenMarker]

51 minutes ago, ProtoflareX said:

Well the two slots on the top of the case I'm buying are unoccupied by default, so I'm planning on getting something to fill those. That being said, my research on case fans is nearing its conclusion. I think I only have two more questions, which hopefully you can help me with. 

 

For my first question, I would like to know what the difference between the two 120mm models linked below is. The first model claims to have a higher CFM while simultaneously having a lower RPM, but I don't understand how that's possible. Doesn't that make it objectively better than the second one?

120mm Noctua fan #1

120mm Noctua fan #2

 

As for my second question, I would once more like to know what the difference between two fans is, but this time, the question concerns two different 140mm models.
140mm Noctua fan #1

140mm Noctua fan #2

The NF-S12A is designed for more airflow whereas the NF-F12 is designed for more static pressure. Optimizing for airflow will often result in a design that sacrifices static pressure and vice-versa. You'll notice that fans optimized for airflow will tend to have more blades at steeper angles. Optimally, you want as much airflow as possible while having enough static pressure for where the fan is being used. 

The NF-A14 and NF-A15 are the same fan with a different frame.

[ProtoflareX]

6 minutes ago, WoodenMarker said:

The NF-S12A is designed for more airflow whereas the NF-F12 is designed for more static pressure. Optimizing for airflow will often result in a design that sacrifices static pressure and vice-versa. Optimally, you want as much airflow as possible while having enough static pressure for where the fan is being used. 

The NF-A14 and NF-A15 are the same fan with a different frame.

Unfortunately, I'll have to pester you with one more question. You mentioned "enough static pressure for where the fan is being used". When you say "where it's being used", you're referring to which slot it occupies in the case, correct? Assuming that I needed a fan to occupy the single back slot of the case, which between the two would you pick?

[WoodenMarker]

1 minute ago, ProtoflareX said:

Unfortunately, I'll have to pester you with one more question. You mentioned "enough static pressure for where the fan is being used". When you say "where it's being used", you're referring to which slot it occupies in the case, correct? Assuming that I needed a fan to occupy the single back slot of the case, which between the two would you pick?

The rear mesh is fairly open so the NF-S12A is much better. The difference is pretty drastic over the NF-F12 since both fans are fairly extreme on either end of optimizing for static pressure and airflow. There are very few situations where I'd recommend the NF-F12 as a rear exhaust since it sacrifices a lot of airflow for static pressure. As mentioned, I recommend seeing how the stock fans perform first. That being said, the NF-S12A is one of the best options available for a low restriction rear exhaust. 

[ProtoflareX]

2 hours ago, WoodenMarker said:

The rear mesh is fairly open so the NF-S12A is much better. The difference is pretty drastic over the NF-F12 since both fans are fairly extreme on either end of optimizing for static pressure and airflow. There are very few situations where I'd recommend the NF-F12 as a rear exhaust since it sacrifices a lot of airflow for static pressure. As mentioned, I recommend seeing how the stock fans perform first. That being said, the NF-S12A is one of the best options available for a low restriction rear exhaust. 

You and the other contributors have been invaluiable in my pursuit of crafting an efficient, futureproof rig. Thank you, sincerely.