Wow - didn't know it was so important to type like some minority here now.
A few points - some repeated from good posts above...
Fans *are* important and more is better regardless of what Putz says. More air through the box means a lower temperature in the box. Lower temperature air in the box means a larger temperature gradient across the heatsinks and into the air. Heat flows faster and parts run cooler. Lower temperature parts means fewer errors, lockups, and longer reliable lifetime. All facts - plain and simple.
Matching air in and out of the box is good practice - I wouldn't have all fans facing out unless you have a huge hole somewhere to allow air in. The more air that has to find its way into the box, the more dust that will fall out and screw up your CD-ROM drive, floppy drive, etc.
It's also good practice to plan the airflow. I have exhaust fans at the top and intake fans and holes near the bottom of my case. Since heat tends to rise, the chimney effect just helps cooling be all the more effective.
Attention spent on card placement is also important. Don't sandwich power hungry cards like the hot graphics CPUs between other cards or away from air flows. Also a good idea is to leave a slot cover or two off the backplane area to help let cool outside air in right under the hot cards, over other heat sinks, or near the CPU. You can use other cards to help channel the airflow where you want it.
I've even got two small exhaust fans discreetly mounted to the top outside of my monitor to help get the heat out of that. You can drive away the winter chill on most monitors but the case of mine stays room temperature. I've been doing this for years and have never had a monitor failure.
Cooling is an important issue. Anyone who really has been overclocking and tweaking since he was a child would know that. Properly-channeled forced air cooling is way the heck better than case-open convection. It's just no contest. It's best to throw everything at the problem as the lower the temperature of the parts, the better off you will be and the more reliable your system.
It's also important to make sure there is a proper thermal connection between CPU and heat sink. In the plastic and ceramic package CPU days, it was easy to goop it up with thermal grease. Now there are various thermally-conductive foams and indium foils that are used. Always good to double check that this very important component of cooling is properly in place.
My brother bought a computer that kept locking up and dying on him after it had been on for a while. Turns out some idiot at the shop had been sticking the paper warranty label on the CPU - actually insulating the CPU from the heatsink and creating a dead air space over the rest of the CPU surface.
And it is important to get in and dust occasionally. Lots of air through the box means more dust that will try to plate out on heat sinks, chips and such. Any dust layers dramatically reduce cooling efficiency and need to be cleared out every now and then. I use spray duster to blow the case and power supply out every now and then and it does throw up a cloud.
I've got a few thermistors sprinkled around my box (ASUS motherboard supports multidrop temperature reporting) and my system runs cool. It's also a very reliable system - I am quite sure because of that and in spite of being overclocked.
And Tyro is ever so right! All this hot new hardware is susceptible to static. Always ground frequently and best to not work over carpet or on days where you are constantly throwing static sparks. Wrist straps need to be the actual static dissipation variety with high resistance. (Hooking yourself up to ground with just a wire is bad practice and a quick way to die.)
All of that without a single "dat", "dude", "fat", or "freakin". And I even used paragraphs and punctuation. Wow.
[This message has been edited by Renfield (edited 12-28-2000).]
