Airflow

[Linchpin]

Dudes,,, with a PC case setup,  i have 2 exhaust fans. What is best.. One for hot air out, one for cold air in, both on cold air in, both on hot air out??

[Wain]

Most of the multiple fan setups I've seen have an intake in the front,
and multiple outs at the back, I have no idea what the preferred method of airflow according to an ATX spec is though.

Regardless, I don't think I've ever seen a fan pulling air in at the back of the case, only out.

[bloodline]

A good rule of thum is to have the same number of fans drawing air in as are blowing it out... remember that the Power supply has one blowing out...

[ksk]

Throw away the x86 motherboard and then throw away fans... next gen Amiga systems do not need extra fans...

(For my A4kT I have one fan sucking air in the case (at bottom front of the case) and the PSU fan removes the hot air from upstairs)

[Lo]

Both on hot air out, definately.  Ensure an inlet vent near the
bottom front, and the fans to be higher up in back.  
(Suck in cold air, heated by components, rises and out the back).    

[Linchpin]

x86?? Hell No! This is my a1200 in tower case :-)

Ok ok so ATM it runs cool enough.. but not for long :-)

The PSU is at the bottom, fan facing upwards of course.

Any more suggestions?

[Amiga4k]

I am not familiar with A1200 tower kits. So, my answer will relate to generic towers.  (But I do have an A4000 in a Power Tower).

The front panel should contain a grill. It may look like louvers, but it allows "air" into the cabinet.  Airflow is based on CFM.
Anytime you increase the "outflow CFM", you need to either (1) increase the space between the louvers, or (2) add an "inflow CFM" fan.  Maximum effect dictates that "inflow" be as far away from the "outflow" as possible.

From your description,  the power supply is at rhe bottom of the case, and vents internally into the tower. The flow is  upward. If you have a expansion slot just above the power supply (and enough room), I would suggest a blower style fan. The ($17) Antec Cyclone 77094-1 will provide 22 CFM at 28 db noise (3yr warr).  If you want more power, the ($10) Alpha/Omega FC2000-B provides 42 CFM at 30 db noise (5 yr warr).
There are fans that install into any unused drive bay, replacing the cover plate that can improve the "inflow". The better styles come with filter material that can be cleaned or replaced.

I have drives that were run 24/7/365 for over 7 years, without failure. These drives operated at 85-115F.  The saving grace was forced ventilation at over 60 CFM.