Should case fan cool or exhaust

[callan]

I'm building a Pentium 4 1.5GHz system, and to keep my components running cool, I'm installing a standard case fan. My question is this: should I have the fan blow out the hot air, or suck in cooler air to circulate? My guess would be to exhaust the case, but I'm concerned that the hot air I'd be exhausting would get sucked into the power supply's intake fan. The power supply is ATX 2.03 and 400W, so I would definitely like to keep that guy cool as well.

Advice would be appreciated.

-Andrew

FAIW, I'm building a P4 1.5GHz, ASUS P4T mobo, 256mb PC800 Samsung RDRAM, GeForce2 GTS 64MB, WD ATA/100 40GB

 

[TonyH]

My suggestion would be both,
I think that you should have at least two fans.
One placed low in the front, where you've probably got a fan bracket to suck in cool air. A second fan high in the rear of the case to exhaust hot air.
This way you have a steady exchange of air.

 

[KouklatheCat]

I agree with TonyH. You should have one exhaust and one intake. They should be fairly equal in cfm from what I have been told. Check out my web page on my profile to see what I did to my case. Which case are you using???

 

[AznBruin03]

yeah, you should have both. Usually intakes in the front and exhaust in the back. If you don't plan on overclocking, you may be able to get away with just one intake fan plus your power supply fan. Or some people just have a power supply fan. Depends on how hot your system gets.