Negative vs Positive air pressure?

Toggle sidebar Toggle sidebar
R

reubenno

Distinguished
Sep 2, 2012
533
0
19,010
Hello,
I am thinking about purchasing some new fans for my Corsair Carbide 300r case in order to keep it cool as I have heard that the cooler the case is, the longer the PC will last. I have decided to get the Corsair AF and SP fans but I am unsure of whether to have negative, neutral or positive air pressure in the case. I have heard that negative air pressure is good as it keeps the PC cool but sucks in dust and that positive is also good as it keeps dust out but it does not provide as much cooling? The case I have has an 140mm front intake fan and an 120mm back exhaust and I was looking at putting an 120mm front intake fan with the other 140mm one and also adding an 140mm exhaust fan at the top of the case.

Any thoughts?
Thanks
 
Solution
KrzysiekX10
Positive pressure - more intake than exhaust
Negative pressure - more exhaust than intake

Both of them have valuable advantages.
Positive pressure gets you less dust inside your case, but it is a bit against the laws of physics; hot air has bigger volume, so getting lots of intake fans and less exhaust fans means that the hot air is not effectively pulled out of the case and the cooling performance is worse.
Negative pressure is pretty much the opposite: better cooling performance but more dust.
Neutral pressure is of course something in between.

So I think it's up to your preferences.

Hope I helped.
Sort by date Sort by votes
KrzysiekX10

KrzysiekX10

Honorable
Apr 6, 2014
89
0
10,660
Positive pressure - more intake than exhaust
Negative pressure - more exhaust than intake

Both of them have valuable advantages.
Positive pressure gets you less dust inside your case, but it is a bit against the laws of physics; hot air has bigger volume, so getting lots of intake fans and less exhaust fans means that the hot air is not effectively pulled out of the case and the cooling performance is worse.
Negative pressure is pretty much the opposite: better cooling performance but more dust.
Neutral pressure is of course something in between.

So I think it's up to your preferences.

Hope I helped.
 
Upvote 0 Downvote
Solution
ingtar33

ingtar33

Glorious
Dec 17, 2012
9,017
198
45,840
in my experience if you have a good airflow case and propper fans there is almost no difference in temps between positive and negative pressure. in a case with poor airflow, generally you'll see a small advantage going with negative pressure.

If you live in a dry, dusty climate, it's almost required to go with positive pressure. as the dust buildup is extraordinary with negative in places like phoenix or other like places in the SW.


the example cited above (about positive pressure) is only true if your case lacks top ventilation. I have an antec 902... it's set up with a positive pressure. however it still has excellent ventilation due to the big 200mm fan on the top of the case. Just because i'm drawing a LOT of air into the case doesn't mean i can't be venting a LOT of air too. In my experience a case with excellent airflow trumps a case without 10 times out of 10 no matter how it's set up.
 
Upvote 0 Downvote
R

reubenno

Distinguished
Sep 2, 2012
533
0
19,010


Okay thanks, I may go neutral then as my case does have fairly good airflow but it can get quite dusty due to the room it is in.

 
Upvote 0 Downvote
R

reubenno

Distinguished
Sep 2, 2012
533
0
19,010


Okay thanks. I think im gonna get an 120mm fan on the front and then an 140mm fan on the top which will make the case neutral pressure wise. I live in Scotland so dusty environment isn't much of an issue. Also what do you think about the fans I have chosen?
Thanks again

 
Upvote 0 Downvote
ingtar33

ingtar33

Glorious
Dec 17, 2012
9,017
198
45,840


they're solid fans... unremarkable excepting for the pretty colored rings you can put on them (that's not a knock on them... they're good fans... just not "amazing").

 
Upvote 0 Downvote
R

reubenno

Distinguished
Sep 2, 2012
533
0
19,010


Okay, are there any else you would recommend for around £10 per fan?
 
Upvote 0 Downvote
ingtar33

ingtar33

Glorious
Dec 17, 2012
9,017
198
45,840
at the £10 mark? probably not. if you're getting them for £10 each thats actually a good deal. i'm now a little more positive about the buy.

the only fans i might suggest instead would be more expensive (Scythe Gentle Typhoon AP-15, or pick your fav Noctua)... so for £10 it's a good buy.
 
Upvote 0 Downvote
G

GorfTheFrog

Distinguished
Aug 12, 2009
183
1
18,815
Hi -
Once you get set up, be sure to check if there is any impact on the airflow across your PSU and/or graphics card. I was running my machine for some time with all the fans running at full, and then I realized that the outflow fans were overpowering the inflow fans to the point where the outflow was pulling air *backwards* through both my PSU and my graphic card.
I switched down the speed on the outflow fans, and I'm still keeping good temps but no longer forcing air through the PSU and graphics card against the natural flow.

Hope this helps.
 
Upvote 0 Downvote
R

Rez_

Reputable
Oct 1, 2015
30
0
4,530


Should i buy 2 intake fans and 1 exhaust fan, or 3 intake fans and 1 exhaust fan? My case is the Define S and i'm using the BeQuiet Silent Wings 2. :)

PS. i have the MSI GTX 970 and the Dark Rock TF as the CPU-cooler. :)
Thank you!
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom