6 x 120mm or 4 x 140mm case fans

[Clarifiante]

hi there, i've got a phanteks enthoo evolv atx case. very sexy, love at first sight kind of moment

 

it can accommodate 3x120 or 2x140 in the front and on the top. and 1x140mm at the rear

 

i plan to install a kraken x61 radiator on the top. 

 

being an absolute noob and assuming i dont care that much about noise (nothing industrial of course), which combination would provide better temperatures?

 

thanks!

[Curufinwe_wins]

Generally speaking 2 140mm fans at the same loudness generate about as much airflow as three 120mm fans.

 

I would personally say 140mm all the way.

[TheKDub]

Go with the largest fans you can, that way they can run at a lower speed while moving roughly the same amount of air, which can make your PC a bit quieter as well.

[vanished]

Well it should be which ever has the most flow, which should be the 6 x 120 based on my calculations (just guessing based on total surface area)

[WoodenMarker]

Well it should be which ever has the most flow, which should be the 6 x 120 based on my calculations (just guessing based on total surface area)

4x 140mm's have more surface area than 6x 120mm's when disregarding the frame and hub which don't produce airflow.

[vanished]

4x 140mm's have more surface area than 6x 120mm's when disregarding the frame and hub which don't produce airflow.

not last time I checked... if we disregard the frame like you said, they are a circle.  Now:

 

6 * pi * (0.120m / 2)^2 = 0.067858 m^2

4 * pi * (0.140m / 2)^2 = 0.061575 m^2

 

Am I missing something?

[WoodenMarker]

not last time I checked... if we disregard the frame like you said, they are a circle.  Now:

6 * pi * (0.120m / 2)^2 = 0.067858 m^2

4 * pi * (0.140m / 2)^2 = 0.061575 m^2

Am I missing something?

The hub?

4(3.14 * 70 * 70 - 3.14 * 44 * 44) = 37227.84

6(3.14 * 60 * 60 - 3.14 * 42 * 42) = 34590.24

[vanished]

 

The hub?

4(3.14 * 70 * 70 - 3.14 * 44 * 44) = 37227.84

6(3.14 * 60 * 60 - 3.14 * 42 * 42) = 34590.24

 

Good point.  But I just measured mine and the hub isn't that big.  If the hub for both was 3 cm the 6 120s are still more.

 

OP, we need exact measurements

[Clarifiante]

not too sure which measurements you're asking for but these are the case measurements:

 

230 mm x 495 mm x 510 mm (W x H x D) 9.25 in x 19.5 in x 20.1 in 

[Curufinwe_wins]

Good point.  But I just measured mine and the hub isn't that big.  If the hub for both was 3 cm the 6 120s are still more.

 

OP, we need exact measurements

Or you can just recognize that 140mm fans are much more efficient on a noise per airflow perspective, and are at least within the margins of error of overall airflow (assuming similar fan profiles which is a really bad assumption.)

[vanished]

not too sure which measurements you're asking for but these are the case measurements:

 

230 mm x 495 mm x 510 mm (W x H x D) 9.25 in x 19.5 in x 20.1 in 

We need the diameter of the solid part in the middle with no blades

 

 

 

The hub?

4(3.14 * 70 * 70 - 3.14 * 44 * 44) = 37227.84

6(3.14 * 60 * 60 - 3.14 * 42 * 42) = 34590.24

 

 

Because I realize we both just made another mistake, or vastly overestimated the hub.  With your calculation the hub would be 8.4 and 8.8 cm respectively - ie, most of the fan.  Definitely not  I threw in 30 instead of 44 but even that is too much since the hub is more like 15 (mm radius)

[vanished]

Or you can just recognize that 140mm fans are much more efficient on a noise per airflow perspective, and are at least within the margins of error of overall airflow (assuming similar fan profiles which is a really bad assumption.)

Yes 140 (or any larger fan) are generally better overall when taking everything into account, but if we just estimate based on the surface area (which has been started and must be finished now )

[WoodenMarker]

Good point.  But I just measured mine and the hub isn't that big.  If the hub for both was 3 cm the 6 120s are still more.

OP, we need exact measurements

4(3.14 * 70 * 70 - 3.14 * 20 * 20) = 56520

6(3.14 * 60 * 60 - 3.14 * 20 * 20) = 60288

Whoops-- I messed up. I used the diameter of the hubs instead of the radius. 

Also, after some measurements of a few fans, I found that hub sizes can vary a bit ranging from 38mm-42mm but are usually 40mm. 

It seems that 120mm's do have more fan surface area. That being said, airflow is still a bit more complicated than just surface area since the edge of a fan blade will travel faster at the same rpm for a larger fan. 

 

Because I realize we both just made another mistake, or vastly overestimated the hub.  With your calculation the hub would be 8.4 and 8.8 cm respectively - ie, most of the fan.  Definitely not  I threw in 30 instead of 44 but even that is too much since the hub is more like 15 (mm radius)

I was just typing up a response to that. Most hubs are ~40mm though--where are you getting fans with 30mm hubs?

[vanished]

I was just typing up a response to that. Most hubs are ~40mm though--where are you getting fans with 30mm hubs?

My front fan.  The others are larger like you said (up to around 40) but like you said, they vary.  And, yes like I mentioned flow depends on a lot more than the total area, but the 120s would have more area.

[Clarifiante]

these are the ones im looking at http://www.amazon.com/Cooler-Master-JetFlo-R4-JFDP-20PB-R1-Performance/dp/B00E20SSZ8

 

which come in at 120x120x25 with airflow of 95CFM so that brings it to 285 CFM intake

 

their airflow ensures that no combination of consumer 140mm can beat them. because im running a 280mm radiators i assume i dont have any choice but to run 2x140mm on top. and the 1x140mm rear is static.

 

the 140mm fans that come with the case are http://www.amazon.com/Phanteks-140mm-Cooling-Fan-PH-F140SP_BK/dp/B00E9NZV4Y/ref=sr_1_1?s=pc&ie=UTF8&qid=1449305356&sr=1-1&keywords=PH-F140SP

 

which come in at 140x140x25 with airflow of 82.1CFM, brings it to 246.3 CFM exhaust

 

so with this the intake > exhaust. 

 

am i doing it right? lol

 

oh, not sure if this matters but the front intake has a filter

[WoodenMarker]

these are the ones im looking at http://www.amazon.com/Cooler-Master-JetFlo-R4-JFDP-20PB-R1-Performance/dp/B00E20SSZ8

which come in at 120x120x25 with airflow of 95CFM so that brings it to 285 CFM intake

their airflow ensures that no combination of consumer 140mm can beat them. because im running a 280mm radiators i assume i dont have any choice but to run 2x140mm on top. and the 1x140mm rear is static.

the 140mm fans that come with the case are http://www.amazon.com/Phanteks-140mm-Cooling-Fan-PH-F140SP_BK/dp/B00E9NZV4Y/ref=sr_1_1?s=pc&ie=UTF8&qid=1449305356&sr=1-1&keywords=PH-F140SP

which come in at 140x140x25 with airflow of 82.1CFM, brings it to 246.3 CFM exhaust

so with this the intake > exhaust. 

am i doing it right? lol

oh, not sure if this matters but the front intake has a filter

Jetflos do perform very well but they are also very loud. 

[katiekitsune]

if you have pwm headers get the venturi hp-14 fans as they are the best value to performance/quietness ive found