Question Four 140 mm fans, one 120 mm and... a question.

Dowglaslim

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Jul 19, 2019
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Hello guys.

I have a Deepcool Matrexx 70 case and I bought four Scythe Kaze Flow 140mm RGB fans. The case already came with a standard 120mm fan pre-installed (exhaust), and I'm thinking of putting two 140mm fans on top (also exhaust fans), with another two 140mm fans at the front of the case, pushing air inside.

The Matrexx 70 has room for three 140mm fans in the front but, as mentioned, I thought of putting just two in the front area. It's a case that has a closed, glass front - and the fans are in front of a dust filter, which further restricts the airflow.

So I would like to know if there is an "optimal" position for installing the front fans. Is it better to put them together or leave a space between them? or is it better to put three fans instead of two on the front, leaving a 140 mm at the top and the rear 120 mm doing the exhaust?

It is worth noting that this case has a PSU cover on the bottom, where the HD/SSD slots are also located.

Additional data:

  • I will use an Air Cooler Deepcool GTE V2 and my video card is a Galax RTX 3060 12 GB (2 fans)
  • My motherboard is an MSI B560M PRO-VDH (mATX).
Environment data:

  • I live in the northeast of Brazil, with ambient temperatures that often exceed 30 degrees Celsius.
  • Dust is a factor, but not a very serious problem.
  • I live on the coast (more or less 12 km far, actually), with the presence of salt air (some say it best to restrict the airflow in the PC in these regions. Can you confirm?)
Thanks in advance.
 
Last edited:
I'm thinking of putting two 140mm fans on top (also exhaust fans), with another two 140mm fans at the front of the case, pushing air inside.
you want to have a positive pressure inside the case so you want at least slightly more intake than exhaust.

i would set it up with 3x front 140mm intakes, 1x rear exhaust, and 1x top-rear exhaust.
I would like to know if there is an "optimal" position for installing the front fans. Is it better to put them together or leave a space between them?
in theory keeping them together can keep the fans from pulling inside air from the gaps between them and provide slightly more cool outside air to be brought in.
It is worth noting that this case has a PSU cover on the bottom
if it has vented panels included i would use those instead of solid.
I live on the coast (more or less 12 km far, actually), with the presence of salt air (some say it is the best region for airflow in the PC in these cases. Can you confirm?)
what do you mean by, "the best region for airflow in the PC"?

any salt in the air could lead to corrosion for components.
 

Phaaze88

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Nothing will beat finding out doing your own experiments.
People could speculate about positioning all day, but if you don't test, there will be none the wiser.


Kaze Flex, not Flow?
There's 2 versions of Flex: 1200 and 1800rpm.


Look at the design of the case. The top and rear are more open than the front is. Focus fans in those areas first, as that's where fans will have the easiest time moving air. Record what temperatures you get out of it, experiment with other fan configs, and compare.
Then make your choice from there.
 
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Dowglaslim

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Jul 19, 2019
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Nothing will beat finding out doing your own experiments.
People could speculate about positioning all day, but if you don't test, there will be none the wiser.


Kaze Flex, not Flow?
There's 2 versions of Flex: 1200 and 1800rpm.


Look at the design of the case. The top and rear are more open than the front is. Focus fans in those areas first, as that's where fans will have the easiest time moving air. Record what temperatures you get out of it, experiment with other fan configs, and compare.
Then make your choice from there.

I got the 1800 RPM version of the Flex, 140 mm. Really looking forward to see those fans working.

Thank you for your inputs.
 

Paperdoc

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For DUST entry, the filters in front of the intake fans prevent that - just remember to check them and clean from time to time. So that does NOT suggest reducing air flow. However, "salt in the air" is a different issue. IF that salt actually is tiny solid particles of salt crystals travelling in the air, the DUST filters may reduce their intake, too - depends on the crystal size. I don't know of any definitive answer on that item.
 

Dowglaslim

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Jul 19, 2019
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For DUST entry, the filters in front of the intake fans prevent that - just remember to check them and clean from time to time. So that does NOT suggest reducing air flow. However, "salt in the air" is a different issue. IF that salt actually is tiny solid particles of salt crystals travelling in the air, the DUST filters may reduce their intake, too - depends on the crystal size. I don't know of any definitive answer on that item.

On my case, the front fans are in front of the dust filter - a feature criticized in the Matrexx 70. I think the manufacturer wanted to enhance the visualization of the RGB fans...
 

Paperdoc

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I expect you are right that the fans on the OUTSIDE of the dust filter are there to enhance lighting visibility. It is much more common, though, to place fans INside the filters. In the case of a RADIATOR with fans, the rad itself is a big light blocker so the fans on those systems do need to be on the OUTside of the rad. BUT dust filters are not big light blockers. So there really is NO need to arrange that filter behind the fan. Leaving it that way would mean the entire interior of your case is protected from dust (and maybe from salt particles) but the FANS are not. Can you re-locate the fans to be behind that dust filter?
 
Can you re-locate the fans to be behind that dust filter?
i don't see any mounting points on the inside.
unless the filters can be relocated to the other side of the plate, i doubt it's possible.
it does look like there are other filters on the inside of the front-side vents though.
11-853-070-V24.jpg
 
My take is to mount three 140mm intakes in front, however that can be done..
140mm fans move more air quietly.
I would use only a single rear exhaust fan.
It;s job is to direct the front airflow over the central area where the cpu cooler, motherboard and graphics card needs the airflow.
Top exhaust fans tend to redirect the front airflow up and out of the case before it can do any good.

If all of the intake air comes from one source and is filtered, your parts will stay cleaner.

I would not worry about salt air.
I live in Florida, about 100m from the ocean and experience 30c and higher temperatures.
But, we have air conditioning.
I have yet to see any salt related issues on my pc.
Yes, anything outside not made of plastic or stainless steel corrodes.
 

Paperdoc

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I'd advise what JohnBonhamsGhost said in the first reply on Aug. 7. Place ONE of the 140mm fans in the top REAR position. That gives three 140 mm intake on front (intake flow somewhat reduced by dust filters) and 2 exhausts - 140 mm and 120 mm. Likey an ideal balance for small positive pressure inside. Gives good general flow pattern from front to back.

I am puzzled by the filter location - hard to tell from website photos. It appears to show the front dust filter to the outside of a frame for RAD mounting. If you are NOT using a rad, can the FANS on the front be mounted to that frame INSIDE the filters and inside the main front frame itself to take up a little space inside the case?
 
Seems to me that it matters little if the filter is in front of the front intake fans or behind.
All of the incoming air will be filtered, regardless.

All of the incoming air will eventually exit SOMEWHERE, taking component heat with it.
Pressure inside a case will not build up.
Exhaust fans primarily help to direct the airstream pattern.
It should be easy enough to dee if one or two exhaust fans makes any difference at all.
 

Paperdoc

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The only reason here for wanting the dust filters to be on the INtake side of the fans is to protect those FANS themselves from dust and salt in the incoming air. For the rest of the system, it's not important.

Air that flows in MUST come out. But usually you get best total air flow though a csse if the air flow capacities of the intake fans and exhaust fans are close to matched. For purposes or preventing air from leaking into the case past the dust filters at small openings, one tries to arrange for just slightly more intake potential than exhaust. This results in having the air pressure inside the case just a VERY little bit higher than the air pressure in the outside room, so air leaks OUT at cracks.