Direction of the fan on my ATX case???

[shoesup]

I am building a new computer. I bought an ATX case, which has a fan on the right side of the case. This fan takes hot air out of the case. There is another fan on the P-IV CPU chip, and there is another fan at the back of the case as part of the power supply.

I want to add an additional fan to the fan cut-out at the back, top of the case.

Question:

When I install this cooling fan, do I install it to suck air out of the case??? Or, to blow air into the case???

PLEASE HELP !!!

[sdkfz]

blow out the hot air.

Generally, the lower fans suck cool air in and the higher fans blow hot air our, don't try to fight "hot air rises"

For those in the middle it get a little more cagey, but if the mid level are placed over a heat generator (CPU/Video card) then I typically see them blowing cool air in and over the item.

The simpler the air flow the better, that way you do not end up with dead zones where the air just sits or rotates like a whirlpool in a river.

[builderboy]

I would have it blow out the air, atleast that's what I've always done with my rigs.

[Designer]

Normally just a fan at the front sucking in air and one at the rear blowing out is sufficient.

Mine's got a bit weird now. I've got two at the front sucking in, the one on the side as exhaust one at the top as exhaust and the rear sucking in cold air directly aimed at my HSF as I was suffering temperature problems when the room gets hot.