Hardware - Case Fans

[Learner]

I have just picked up a second hand computer (tower) system (with XP) so
that I can "play around" with. The tower has three case fans fitted, one at
the front and two at the rear of the case (both just underneath the power
supply). What I was wondering is, in which directions should these fans be
working? Blowing air into the case or extracting air from the case?

 

[Jerry]

You don't want the fans set to work against each other. I have the one in
front oriented to pull air into the case and the one in back oriented to
blow air out of the case. This results in air flowing from bottom to top in
the case. (Remember, cooler air is lower in the room and hot air rises.)

 

[Learner]

Thanks Jerry.

You don't want the fans set to work against each other. I have the one in
front oriented to pull air into the case and the one in back oriented to
blow air out of the case. This results in air flowing from bottom to top
in the case. (Remember, cooler air is lower in the room and hot air
rises.)

 

[Og]

I have just picked up a second hand computer (tower) system (with XP) so
that I can "play around" with. The tower has three case fans fitted, one at
the front and two at the rear of the case (both just underneath the power
supply). What I was wondering is, in which directions should these fans be
working? Blowing air into the case or extracting air from the case?

AMD has this to say about cooling (watch for hyperlink wrap):
Air Flow
In a typical desktop tower form factor, air should flow in from the bottom
front of the case and exhaust out the top rear of the case. Ambient air
temperatures inside the case will play a large role in the effectiveness of
individual solutions used for the processor, video card, and chipset.
Therefore, expelling excess heat is essential for proper cooling and
stability.
http://www.amd.com/us-en/Processors/ComputingSolutions/0,,30_288_13265_13295^13333,00.html#AirFlow

Steve