Case Fan Orientations

[Hooya]

I know it's probably been discussed before, but I'm just gonna ask it anyways.
On a standard atx case, would it be better to orient the rear case fan to pull air into the case or suck air out of the case? Can anyone explain why either way is better or worse?

I have a Tbird 900 on ASUS A7V, so the cpu fan is sitting rather close to the rear case fan's location, if that matters.

Thnx

 

[John]

Suck in from the front of the case and blow out the rear. You want a "wind tunnel" effect.

 

[drewski]

bottom front, into case.
rear fan by CPU, out of case.

it's a natural flow of air with hotter air rising. exhaust should be higher up on the case and in-flow lower down. there is a nice diagram on the AMD site, which i may look for.

 

[QuestionsandAnsweres]

rear is usually near the top. so taking air out of the case it better than pushing it in. Remember. Heat rises. So sucking heat out from the top will decrease temps more than pushing air in.

 

[QuestionsandAnsweres]

here

 

[drewski]

oohh, was just about to post the same link . . .

 

[waytoomuchcoffee]

Unless your system is really strange, your ATX power supply should be blowing air OUT (that's the ATX spec at least). If you blow air into the lower back, and out the upper back, you "short circuit" the front of the case. That may or may not be a bad idea, depending on your hard drives.

You don't HAVE to have air blown into the front however. Many cases that blow air into the bottom front and out the top back mean that the air has a long way to go to get to the primary cooling spots (CPU and vidcard). If you have a lot of cables and junk, and a constricted case, that air might be pretty warm before it gets there.

My rig, for example of another way to do things, has a 120mm intake in the back, and ducted to blow over the CPU. Air flows out through 1) an 80mm fan mounted at the top of the case (heat rises, so I think everyone should have a fan at the very top 2) my Enermax PS, which has two fans (one intake on CPU side, and one out at the normal PS out spot), and 3) a (very quiet) blower designed for servers mounted right next to the vidcard, blowing out the adjacent slot. The front of the case doesn't get direct airflow, but the overall case is cool enough for the harddrives. Even that link about said a front cooling fan is "not essential".

All in all, not very noisy. I have the 120mm fan controlled by a rheostat that I turn on when I play games, otherwise, it doesn't need to be on, the back airvents provide enough cool intake.

 

[Hooya]

wow, thanks for the help. I guess it all kinda makes sense if I just gave it a little more thought (but I'm just too lazy ) Now that you mentioned it, I'm thinking of drilling a hole on top of my case and installing a fan there too.

thnx again