Sign in with
Sign up | Sign in
Your question
Solved

Improving & understanding airflow

Last response: in Overclocking
Share
February 3, 2013 3:20:59 PM

I have an antec 300 case. I need suggestions or recommendations on how to optimize or improve the cooling on my case. I have added 2 yate loon d12sh fans (used as 2 intake fans), 2 antec fans (default ones with 3 speed control, exhaust fans), 2 ultrakaze 3000rpm fans (used on my cm 212+) and 1 cm fan 1200 rpm (free from cm 212+, used as side panel intake). Is my setup correct or I need to make some adjustments to this one? I don't care about the noise. The ultrakaze is really loud and I am okay with it.

Question: Should I set my antec tricool fans to High or just Low? I am not overclocking anything since there is no need for it.

The reason why I am asking for this is because I am looking for a new case and I want to understand better on what to look for in a case in terms of the cooling part. I am confused with the terms I come across with like airflow, static pressure, negative and positive pressure. So if you can help me understand it better that would be appreciated. (note: I googled those terms but they are explained in a technical way and it confused me more. lol)

Best solution

February 9, 2013 6:34:50 PM

Your set-up doesn't sound problematic, but the number of intakes/exhausts, while important, isn't as important as the locations for those intakes and exhausts. For instance, front, bottom, and side fans should be intakes (sucking cool air in from the outside and blowing it into the case), and rear and top should be exhaust (sucking warmer air out of the case and blowing it outside). If you have one of those rare cases that has a fan mounted behind the motherboard (where cables are usually routed), that should be an exhaust. There are all sorts of different cooling fan configurations; not everyone has a bottom or side fan, for instance, and very few have a fan behind their motherboard. The key is to make your airflow work for you as best you can given your components (i.e.: your case, what you have inside it, and the fans at your disposal) and your budget. Noise is also usually a consideration, but it sounds like you aren't worried about it.

The idea is to keep air flowing as naturally and swiftly as possible, bringing cool air in from below so it can cool the components in your case before being expelled (with the help of convection—hot air naturally rises) out the top and back.

To answer your specific question, the best way to determine what speed you should run your fans at is to experiment. Set them to their lowest speed and monitor your internal temperatures over the course of normal and heavy use. If the temperatures aren't too high, then you can leave the fans at their lowest speed. If it gets too hot, try increasing the speed.

Here's a rundown of those terms you're talking about:

Airflow is simply a term that means how the air moves through your case. High airflow is good; it means there is lots of air moving freely to the appropriate areas of your system and then being expelled. Low airflow is bad; it means that very little air can get into your system to cool it down, or that the air that comes in can't escape and becomes stagnant and hot, which doesn't help to cool your components.

Static pressure is a measure of the obstruction of airflow. I think of it like this: cover your mouth with your hand, keep your fingers together, and try to breathe in or out. Now open your fingers a little and try again. See how much easier that was? The more free the air is around a blower (like a fan), the less work that blower has to do in order to move the air. So, what you need to know is that if you are placing a fan where the air into which that fan is immediately blowing or from which that fan is immediately sucking is obstructed (by a grill, a heatsink, a video card, etc.), you will want a fan with a higher static pressure rating. Pick a case without too many obstructions, though, and you shouldn't really need to worry about this.

Now, negative and positive pressure: Consider a case that has 5 identical 120mm fans running at the same speeds (front, bottom, and side intakes; rear and top exhausts). This case will have more air coming into it than is escaping because there are more fans acting as intakes than as exhausts. This is called positive pressure, and it means that the air inside your case will be fighting to get out (i.e.: the pressure inside the case is higher than the pressure outside the case). Now imagine we take the bottom intake fan and turn it into another top exhaust fan. Now there are 3 exhausts and 2 intakes. This is negative pressure, since air outside the case is fighting to get in (i.e.: the pressure outside the case is higher than the pressure inside the case). Positive pressure means less dust accumulation, while negative pressure means more effective cooling (since the air that's pulled in from outside doesn't have time to stay in the case and become stagnant and hot). So, usually, you want to go with negative pressure, since dust can be dealt with by simply using some compressed air, dust filters, and the like.

Here's the thing you want to consider when looking at what your case's pressure is going to be: A single 140mm fan will most likely move more air than two 92mm fans. All fans have a CFM (Cubic Feet of air per Minute) rating that tells you how much air your fan moves (higher CFM means it moves more air). To determine your case pressure, add your individual intake fans’ CFM ratings (usually mentioned on the fan housing or motor itself), and compare it to the total of your exhaust fans' CFM ratings. If the total intake CFM is greater than your total exhaust CFM, you have positive case pressure. If total intake CFM is lower, you have negative pressure.

Hope this helps!
Share
February 9, 2013 11:27:51 PM

Best answer selected by jaypeeb421.
m
0
l
Related resources
a b K Overclocking
February 9, 2013 11:38:00 PM

Nice write up SyntaxSocialist

Simplify what he said, you generally want air to go front of case to back of it and out and heat rises so intake down low and exhaust up high.

Beyond that you can hit a point where you have adequate air flow and adding more air flow will only net a small amount of increase in cooling effecienty from what I've seen in my setup and several other people setups. So going with the highest air flow fans aren't always necessary. What is more important is to have proper airflow and an adequate amount of it.

For this your Antec 300 is a good case in the layout and should have proper airflow (direction). And the fans you have will provide more than enough CFM. So your main concern will be making sure there are as few of obstructions as possible. Things such as bad cable management should be fixed and cleaned up to provide a nice clear path for the air. Air filters obstruct air flow, so if you wanted best cooling and your using that get rid of it, just clean your computer more as it will get dusty. Fan grills create obstruction to air how much depends on the design, more so than you think. Though from what I have seen antec is quite good on this and are generally quite acceptable in my opinion so I wouldn't worry. And generally clear out anything out of the path for airflow that you resonably can and your good.

And go ahead set your tri fans to low if you want, if your not overclocking I doubt you need this much cooling. I have an Antec 900 and my tri-fans are set to low and my computer is OC, I also have some very high CFM fan that I decided not to use in the side window and instead opted to put an slow quite one there as there was no point. It more than cools my computer adequately. Heck my fan on my aftermarket tower heatsink bit the dust a year ago so I removed it and have just been relying on the top and side fans to move air through it and temps have only risen a couple celsius due to it (it was low enough that at idle I think it was 10 celsius over ambiant or something and would use it as a temp gauge for my room).
m
0
l
a b K Overclocking
February 10, 2013 1:07:51 AM

assasin32 said:
Nice write up SyntaxSocialist

Simplify what he said, you generally want air to go front of case to back of it and out and heat rises so intake down low and exhaust up high.

Beyond that you can hit a point where you have adequate air flow and adding more air flow will only net a small amount of increase in cooling effecienty from what I've seen in my setup and several other people setups. So going with the highest air flow fans aren't always necessary. What is more important is to have proper airflow and an adequate amount of it.

For this your Antec 300 is a good case in the layout and should have proper airflow (direction). And the fans you have will provide more than enough CFM. So your main concern will be making sure there are as few of obstructions as possible. Things such as bad cable management should be fixed and cleaned up to provide a nice clear path for the air. Air filters obstruct air flow, so if you wanted best cooling and your using that get rid of it, just clean your computer more as it will get dusty. Fan grills create obstruction to air how much depends on the design, more so than you think. Though from what I have seen antec is quite good on this and are generally quite acceptable in my opinion so I wouldn't worry. And generally clear out anything out of the path for airflow that you resonably can and your good.

And go ahead set your tri fans to low if you want, if your not overclocking I doubt you need this much cooling. I have an Antec 900 and my tri-fans are set to low and my computer is OC, I also have some very high CFM fan that I decided not to use in the side window and instead opted to put an slow quite one there as there was no point. It more than cools my computer adequately. Heck my fan on my aftermarket tower heatsink bit the dust a year ago so I removed it and have just been relying on the top and side fans to move air through it and temps have only risen a couple celsius due to it (it was low enough that at idle I think it was 10 celsius over ambiant or something and would use it as a temp gauge for my room).


Crazy mofo
m
0
l
February 10, 2013 11:25:34 AM

thanks for the reply guys. just a followup. what will be a good replacement to my exhaust fans. the antec 300 fans on the exhaust (top and rear) are now kinda old. im looking at corsair quiete edition fans. will this work? i just want to balance the air flow as what you guys suggested. i just want the best parts for my pc :) 
m
0
l
!