[SOLVED] Exhaust fan and CPU Cooler

[ridahwouters]

As someone rather new to PC building, I only recently became aware of the distinction between 'static pressure' and 'air flow' fans. I am building using an NZXT h500 and I am making use of a Cooler Master Hyper 212 CPU cooler. Now the NZXT H500 comes with 2 pre-installed (exhaust?) fans, one at the back and one at the top.
My question therefore, is given the space between these fans and the CPU cooler I am using, would it be better to make use of static pressure or airflow fans should I replace the stock?

 

[jeremyj_83]

You would be better off getting 2x 140mm fans to put at the front intakes.
I personally have had good luck with my Prolimatech fan and they have a 140mm with high CFM and is quiet. https://www.newegg.com/prolimatech-pro-usv14-case-fan/p/N82E16835242033

 

[ridahwouters]

You would be better off getting 2x 140mm fans to put at the front intakes.
I personally have had good luck with my Prolimatech fan and they have a 140mm with high CFM and is quiet. https://www.newegg.com/prolimatech-pro-usv14-case-fan/p/N82E16835242033

Thanks for taking the time to respond. I have indeed already obtained two 140mm static pressure fans for the front as it has proven best given the closed front of the case, however, due to aesthetic reasons, i'm considering replacing the standard black NZXT case fans, thus the reason for my question.

 

[jeremyj_83]

I personally like to make sure that I have more CFMs entering the case than leaving which give you a positive pressure case. https://www.silverstonetek.com/techtalk_cont.php?area=en&tid=wh_positive If you replace the top fans to have a positive pressure case you will want those to have lower CFMs than your intakes.

 

[ridahwouters]

I personally like to make sure that I have more CFMs entering the case than leaving which give you a positive pressure case. https://www.silverstonetek.com/techtalk_cont.php?area=en&tid=wh_positive If you replace the top fans to have a positive pressure case you will want those to have lower CFMs than your intakes.

Aah I see what you're saying. I have two Corsair SP140 for the front of the case, since the NZXT h500 only has a thin vent on the side. But I noticed now the CFM is only basically 50 whereas the CFM for the stock AER f120 fans is just over 60. So I guess only the logic of the link you posted, it will result in a negative pressure, which is bad. Going to have to figure out how to fix this then.

 

[jeremyj_83]

Aah I see what you're saying. I have two Corsair SP140 for the front of the case, since the NZXT h500 only has a thin vent on the side. But I noticed now the CFM is only basically 50 whereas the CFM for the stock AER f120 fans is just over 60. So I guess only the logic of the link you posted, it will result in a negative pressure, which is bad. Going to have to figure out how to fix this then.

You could place the stock fans in the front and the other ones in the back. Otherwise the fans I linked earlier are around 90 CFM.

 

[ridahwouters]

You could place the stock fans in the front and the other ones in the back. Otherwise the fans I linked earlier are around 90 CFM.

This is, after doing some research, SP fans are recommended for the front given that its basically closed and SP fans do better at moving air in instances such as these. So I mean, is it incorrect to assume that the specified CFM would not even matter if all the air was obstructed?

 

[jeremyj_83]

I think you are right in your assumption, but it is hard to guess. Your intake fans are going to be sucking in air through those side vents so SP fans would make sense.

 

[ridahwouters]

I think you are right in your assumption, but it is hard to guess. Your intake fans are going to be sucking in air through those side vents so SP fans would make sense.

Ye, I think it would be easier if there weren't so many conflicting opinions about fan placement in this damn case lol.

 

[ridahwouters]

I'm considering two Corsair AF120 fans which match the SP fans in color, and are only slightly high in CFM, which technically, could at least get me a balanced air flow as opposed to overly negative or positive.

 

[jeremyj_83]

Makes sense.

 

[Phaaze88]

You need to look at the static pressure rating as well, as the CFM rating alone does not tell the whole story.
You could have fans with 90cfm, or some other high number, but if it has low static pressure... the moment you put it against some obstacle, it's pretty much moving no air at all.
These fans tend to work best as exhaust, as there's generally no other resistance aside from the case frame.
A static pressure of at least 1.5 is good for intakes.

 

[ridahwouters]

You need to look at the static pressure rating as well, as the CFM rating alone does not tell the whole story.
You could have fans with 90cfm, or some other high number, but if it has low static pressure... the moment you put it against some obstacle, it's pretty much moving no air at all.
These fans tend to work best as exhaust, as there's generally no other resistance aside from the case frame.
A static pressure of at least 1.5 is good for intakes.

Well the SP140's appear to have a static pressure of about 1.2, so unfortunately not as high as you suggested.

 

[Phaaze88]

Well the SP140's appear to have a static pressure of about 1.2, so unfortunately not as high as you suggested.

Well that's not too bad. They would still do better as intakes than the stock fans. Get the SP140s for front intake, and use the stock fans for exhaust.

 

[ridahwouters]

Well that's not too bad. They would still do better as intakes than the stock fans. Get the SP140s for front intake, and use the stock fans for exhaust.

Thanks again for taking the time to respond. Yup, that exactly what I have at the moment (or at least sealed in a box here), two SP140s and the two NZXT aerF120's which come installed as exhaust. I'm however considering replacing the stock fans with Corsair AF120's simply for aesthetics purposes. Would this be considered a downgrade? Or possibly just replacing the back NZXT stock fan and not both?

 

[Phaaze88]

No change between the two fans(aer F120 & AF120) performance-wise. The specs are about the same.
Changing for aesthetics is your choice.

 

[ridahwouters]

This may seem like a silly question, so excuse my ignorance, but when playing two SP140 fans in the front of the NZXT H500. Which way should the fans face? The front of the case (i.e. the front panel) or backwards towards the rest of the case?

 

[Phaaze88]

This may seem like a silly question, so excuse my ignorance, but when playing two SP140 fans in the front of the NZXT H500. Which way should the fans face? The front of the case (i.e. the front panel) or backwards towards the rest of the case?

The air comes out of the side that has a small sticker on it, usually detailing the fans specs. You want that side facing inside the case for intake.
It's the opposite for exhaust fans.

 

[ridahwouters]

The air comes out of the side that has a small sticker on it, usually detailing the fans specs. You want that side facing inside the case for intake.
It's the opposite for exhaust fans.

Sorry I thought the sticker side faced the front of the case as opposed to the inside of the case?

View: https://youtu.be/98ujnl1_hW0

@09:55 it appears that he faces the fans to the front? Is this incorrect?

Edit* - sorry I think I misunderstood you. So the side with the small sticker detailing the fan specs are technically the "back side" of the fan, and that side faces the rest of the case if I'm understanding correctly?

 

[ridahwouters]

So to clarify, If I made use of my two SP140's as intake, with 49.5 CFM and 1.18 mmh20, using exhaust fans with greater CFM will create a negative airflow in which case heat escapes quicker but dust enters easier?
edit* - If I replace the stock exhaust fans with better airflow fans, should I get PWM fans or are 3 pin connecting ones fine?

 

[Phaaze88]

Sorry I thought the sticker side faced the front of the case as opposed to the inside of the case?

View: https://youtu.be/98ujnl1_hW0

@09:55 it appears that he faces the fans to the front? Is this incorrect?
Edit* - sorry I think I misunderstood you. So the side with the small sticker detailing the fan specs are technically the "back side" of the fan, and that side faces the rest of the case if I'm understanding correctly?

Some fans do have stickers on the front and back. I'm talking about the one that also includes the fan's specs, like this:
Front(air is pulled through this side) https://c1.neweggimages.com/NeweggImage/ProductImage/AG7R_131874332828777531CN2e4xXY7s.jpg
Rear(air is pushed out from this end) https://s.yimg.com/aah/outletpc/noc...-sso2-bearing-a-series-blade-geometry-184.jpg
For intake, you want the rear side facing inside the case. The opposite is true for exhaust.

So to clarify, If I made use of my two SP140's as intake, with 49.5 CFM and 1.18 mmh20, using exhaust fans with greater CFM will create a negative airflow in which case heat escapes quicker but dust enters easier?
edit* - If I replace the stock exhaust fans with better airflow fans, should I get PWM fans or are 3 pin connecting ones fine?

Using the fans you already have, 2x Corsair SP140 & 2x Nzxt Aer F120(case stock), you will end up with negative pressure regardless of fan setup, due to the almost identical pressure ratings, and the small gap between the cfm ratings.
You were also considering replacing the stocks with Corsair AF120s, but the situation would be the same.
Consider using Nzxt's Aer P 140s: https://www.nzxt.com/products/aer-p (pressure rating of ~2.70 and cfm of ~98... probably won't help with looks though)
Use those as front intake, and move the stock fans to exhaust - that'll give you positive pressure.

Note that all these numbers and whatnot are with the fans running at max speed. They aren't nearly as high running at 50% and so on.

 

[ridahwouters]

Some fans do have stickers on the front and back. I'm talking about the one that also includes the fan's specs, like this:
Front(air is pulled through this side) https://c1.neweggimages.com/NeweggImage/ProductImage/AG7R_131874332828777531CN2e4xXY7s.jpg
Rear(air is pushed out from this end) https://s.yimg.com/aah/outletpc/noc...-sso2-bearing-a-series-blade-geometry-184.jpg
For intake, you want the rear side facing inside the case. The opposite is true for exhaust.



Using the fans you already have, 2x Corsair SP140 & 2x Nzxt Aer F120(case stock), you will end up with negative pressure regardless of fan setup, due to the almost identical pressure ratings, and the small gap between the cfm ratings.
You were also considering replacing the stocks with Corsair AF120s, but the situation would be the same.
Consider using Nzxt's Aer P 140s: https://www.nzxt.com/products/aer-p (pressure rating of ~2.70 and cfm of ~98... probably won't help with looks though)
Use those as front intake, and move the stock fans to exhaust - that'll give you positive pressure.

Note that all these numbers and whatnot are with the fans running at max speed. They aren't nearly as high running at 50% and so on.

Ye I figured the AF120 and 140 would be similar to the stock fans, but they do appear to have slightly better airflow, lower pressure, and are more quite than the stock fans. If I'm not mistaken though, a negative air pressure is actually better for cooling though? However, by replacing the stock, I'm assuming it will remain negative, but shift more towards a balanced airflow.

Edit* - after reading through Gamernexus tests of the NZXT H500 and its temperatutes, it appears that stock configuration is best for the GPU temp but results in a higher CPU temp. So even if I replaced the stock fans and added 2 intake fans, I've been told I will still end up with a similar negative air pressure system to that of the stock. But on this reasoning, am I correct in understanding that I will have a lower gpu temp but a higher CPU temp, which will ultimately be lowered by an aftermarket CPU cooler, so kind of win win?

 

[Phaaze88]

Yep.

That's the only real downside of aftermarket gpu coolers; that they dump most of their heat back into the case, some of which does get fed into the cpu cooler. But even this isn't a big deal if you've got an aftermarket cpu cooler.
Same deal with dust; it's only an issue for the lazy. Users still need to manually clean out their cases every so often, although some are easier to maintain than others.

 

[ridahwouters]

Yep.

That's the only real downside of aftermarket gpu coolers; that they dump most of their heat back into the case, some of which does get fed into the cpu cooler. But even this isn't a big deal if you've got an aftermarket cpu cooler.
Same deal with dust; it's only an issue for the lazy. Users still need to manually clean out their cases every so often, although some are easier to maintain than others.

Yeah, you're not the first to point out that negative airflow works in that you should be cleaning your case regularly anyway. As a last question, since I feel you have already contributed so much, what is the best (and if possible cheap) way of cleaning your pc?

 

[Phaaze88]

Grab a few compressed air cans, and a couple of damp hand towels or something similar(lint-free, of course).
Take the case outside - you don't want to blow dust back into the room for the PC to suck back up again!
Remove the gpu, psu, any pcie cards, cpu cooler fan(s), case fans - depending on location inside case, you may be able to clean without removing.
Use the compressed air on the mesh filters and all the air 'grilles', the gpu, psu, cpu heatsink, fans, and use the towels to wipe inside and outside the case - basically, what you couldn't do/get with the air cans.
For dust and debris that doesn't easily come out of the mesh filters, just run some water through them, and let it dry.

^This is what I had to do with my old Phantom 820(a monster of a case!). I have recently changed to a Cooler Master H500P Mesh.
I have back problems now, and the size and weight of the 820 -especially when fully loaded - made it a PITA to move around and do maintenance.
The H500P Mesh is smaller, lighter, and far easier for me to work with.

Depending on how the manufacturer's design their cases, some of the above steps can be made easier, or bypassed entirely.
I don't believe the Nzxt H500 will give you nearly as much trouble as my old case did.