Air Flow in CPU Case

**Gkjr** · 09-13-2003, 11:56 AM

Hello Had a question about air flow I have 5 fans one is drawing air in and the other 4 are drawing is this ok or what is the right way
Thanks Jerry

**jasho** · 09-13-2003, 01:01 PM

The basic concept is to have a steady current or flow of air in your system. The setup you have is fine, but where is the fan that is drawing in the air located? That is the main question. I am assuming it is in the front of the case and the other 4 are drawing it out by one on the top, two in the rear, and one in the side?

Conversely, you could have it the other way around as well having one pump out air and 4 drawing in air. Either way, you just want a flow of air into and out of your case.

**DanWalloch** · 09-13-2003, 01:32 PM

I have 2 80mm case fans at the rear drawing warm air from the case and 2 80mm case fans in the front drawing cool air in. I also have a powersupply that has 2 inline 80mm fans (both ends of the psu), which also kind acts as another case fan. Remember hot air is your enemy with a pc, the more you can pull out and replace with cooler air, the better. Also take a look at how the airflow with travel over other fans, ie: cpu, gpu and other small fans, so that you can't creating a vaccum and starving those fans of air to use.

http://sgair.net/mike/banners/dan_w_small.jpg

**rstansbury** · 09-15-2003, 11:13 AM

You should have close to an even number of fans in-out. The fans at the front of the case should blow in, the fans at the rear of case should blow out. If you have a fan on the side, it should blow in on your video card.

**FITZY** · 09-15-2003, 12:59 PM

It has been suggested that ribbon cables in cases significantly reduce air flow. Round cables are said to offer less resistance and better flow.

**jasho** · 09-15-2003, 05:23 PM

Go here:

http://www.hardcorecooling.us/

They have lots of products on cooling. But, I agree with the way fans should be blowing. I have (2) fans in the front of the case blowing in air, (2) fans in the rear blowing out air, (2) fans on the side in front of the CPU and video card blowing in air, and (1) fan on the top blowing out air.

**mavrocket** · 09-15-2003, 06:08 PM

Here's a good idea I learned from someone over at Overclocker's Forums. Keep in mind it requires a side-window on your case. Shut off all the lights (better to do it at dark), grab a flashlight, and an incense stick. Light the incense and then put it out, letting the smoke get pulled into your system. Using the flashlight, watch the smoke as it goes through your system. This will indicate where the primary airflow is.

I agree with the other fellas in also having an equal amount of fans pulling in and pushing out. Avoid fans that go in your drive bays, as they will interfere with the airflow over your CPU. Also, when counting in-and-out fans, do not count the PSU fan(s).

Getting a side-fan, something like a 92mm Stealth will help your video card and cpu by adding that much air. And the air doesn't have a chance to be diverted by ribbon cables and the mass of power-tentacles. Regardless of what anyone says, side-fans HELP. That is, unless you are pulling the air right back out through a PCI slot (GeForce Pratt and Whitney 5800 excluded, since that is the idea), with a Cyclone fan, also something to avoid since it pulls air away from your CPU.

Good luck.

**rstansbury** · 09-16-2003, 04:22 PM

Strange, I used to have one of those slot fans, and after experimenting I found that my case ran hotter with it in. I came to the conclusion that because it is close to the bottom of the case all it was doing was removing the cold air that was coming in from the front of the case. I did try to install it directly below my video card (to draw the hot air from the card out), but there was not enough clearance for it there.