General case cooling fan question

M

mfm

Guest
I have searched the various forums and stickies, and I have not found any specific guideline to my question. When adding cooling fans to a case, how should the fans oriented?

I've encountered opinions ranging from:

  • use intake fans only (and exhaust air through vents, typically in the rear of the case)
  • use exhaust fans only (and intake air through vents, typically in the front and side of the case)
  • use a combination of intake and exhaust fans
Others have added the suggestion to add a blowhole to the top of the case and add an exhaust fan there.

Any suggestions or a link that might provide some advice? Thanks. :)
 
If you can fit them, 2x80mm fans in, 2x80mm fans out and a hole in the side of the case with tumble dryer hose straight onto the cpu fan.
The airflow will be pretty balanced with the PSU fan and maybe gfx card fan blowing out.

Cooling the cpu like this not only makes the CPU cooler but also gives cooler air from the CPU heatsink into the system.
 
never use method 2, all it leads to is dust dust and more dust

and i wouldn't use method 1 either


too much positive or too much negative pressure in the case is a bad thing for air flow and dust building up, try and balance it out best you can
 
for an average case, you have one intake in the front bottom and one in the rear towards the top. like 133 said balanace intake and exaust. you dont have to be exact the case will draw in air thought every crak or bleed air though every crack. just intake or just exaust will preform poorly, fans are not great at makeing air pressure.

personaly i cut out every incase fan grill and replace it with a thin wire or plastic one for less air reistance. top of the case blowhole's are great for normal cases heat rises and the power supply dont draw much air and the rear exaust if never high enough.

if you get a high end case most of the time most things are taken care of. normal cases need moded.
 
gesicht said:
personaly i cut out every incase fan grill and replace it with a thin wire or plastic one for less air reistance. top of the case blowhole's are great for normal cases heat rises and the power supply dont draw much air and the rear exaust if never high enough.
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I understand what you are saying. The typical vents in many PC cases tend to restrict the airflow into and out of the case, and mine is no exception. I have two intake fans in the front, two exhaust fans in the rear (plus the power supply fan), and one intake fan at the side. Despite the large number of fans, airflow seems to be restricted because of the default setup with the case. This is something I will think about when I build our next PCs.
 
its worth doing, I forgot to mention it, cheers gesicht.
The fans run quieter as well as push more air.

My case has big holes where the fan grills were :D
 
Chernobyl1 said:
its worth doing, I forgot to mention it, cheers gesicht.
The fans run quieter as well as push more air.

My case has big holes where the fan grills were :D
Click to expand...
Looks like it is time for me to purchase a Dremel! ;)
 
check out the work log sub forum. you can see many cases layouts and the use of 120 mm fans is a big jump for air cooled cases low noise, great air movement. also look at their cable management. keep everything out of the way to let the air flow smooth.

if you have generic 80 mm fans mounted to your case you are not going to be moving that much air. plus if you have a case that lets the video card divide the case in thirds it will be a problem. if you have 3 intake and 3 outtake you should be good as long as they are moving air. i just have a feeling they are not moving that much air.

but for your next build just look at the cases out there. i like the thermaltake armor case dont use the lower hard drive mount and use the one up top next to power supply. or the CM stacker 810 the one that doesn't look stupid. or li lian p180 all great cases for moving air.

air needs room to move
 
I agree 120mm fans are really good.
Unfortunately I have only seen 1 case in person that can take them as standard.
I couldnt cut a 120MM hole in my case, theres no room sadly.
 
I've found my perfect noise cooling ratio setup: 2x 120mm intake 55cfm, 2 120mm exhaust (including psu) and a 80mm on the side blowing cool air directly into the 89cfm 120mm on top of an SI-128 keeps my 4400+@2.5 at a cool 34c idle. The way to tell if you need a blowhole or not is to feel the top of your case after a gaming session...if it's cool then you have good airflow and don't need to bother with a blowhole.
 
Chernobyl1 said:
I agree 120mm fans are really good.
Unfortunately I have only seen 1 case in person that can take them as standard.
I couldnt cut a 120MM hole in my case, theres no room sadly.
Click to expand...
There are a lot of cases available with room for 1-4 120mm intake/exhaust fans.
 
So would a side intake fan and blowhole be sufficient enough to get good airflow?
 
Your setup is close to optimal.
Feed the air in from the side directly onto the cpu to help reduce cpu and therefore case temps.
Dont fit a blowhole on the side of the case, it shouldnt be necessary.

You have 2 fans blowing in at the moment and 3 fans out.
With the CPU fan drawing air in you will have 3 fans blowing in as well as out.
The CFM of the fans counts but I'm not privvy to that info.

If you feel the need to address any air pressure imbalance, remove the blanking plate below your graphics card.
Air will either flow out of the hole or in the hole, either helping keep warmer air out of the case or keeping the graphics card a little cooler.
I place a little piece of cardboard angled upwards between the gfx card fan out slot and the open slot below it to prevent hot air recirculation.
You can use a lower blanking plate hole instead/aswell though.

Cut the fan holes out to get the most from each fan.
 
Danny Bui said:
So would a side intake fan and blowhole be sufficient enough to get good airflow?
Click to expand...
I've found that the side intake is only really useful if your heatsink is something like the SI-128, Big Typhoon or any other heatsink where the fan is parallel to the board...the popular "stand up" heatsinks don't really benefit. Like I said earlier..a blowhole is only needed if the top of your case frequently gets warm.

edit- A side intake located a little lower...at videocard level would still be useful even if you have a standup sink.
 
Another cooling setup to consider (the one I use):

- One 120MM fan as a front intake.
- One 120MM fan in the "blowhole" position as an intake.
- Two 120MM rear exhaust fans.
 
joemama said:
I've found that the side intake is only really useful if your heatsink is something like the SI-128, Big Typhoon or any other heatsink where the fan is parallel to the board...the popular "stand up" heatsinks don't really benefit. Like I said earlier..a blowhole is only needed if the top of your case frequently gets warm.

edit- A side intake located a little lower...at videocard level would still be useful even if you have a standup sink.
Click to expand...

Well unfortunately, my case already comes with a side intake at CPU level and blowhole.
 
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