A lot has been written about cooling your tower PC case. Modern processors run hot, and can reach temperaturs of up to 75 degrees celcius (C) or 158 degrees fahrenheit (F). The inside temperature of the case can reach 40C or 104 degrees fahrenheit. At these levels your computer can shut down, the processor can burn.

The typical cooling method of a case is to have a fan blowing air in from the bottom front, and the air going up and sucked in to the power supply then out the case, also, this air passes by the CPU, which also (hopefully) has a fan blowing on it's heat sink. However, with the newer processor case manufactures have added a fan in the back to assist the power supply blowing air out.

Modern CPUs (Processors) require high-powered fans and a heat sink to keep it a decent temperature. A heat sink is a simply metal fixture with fins, can be aluminum, copper or metal, which the heat goes on and dissipates as the fan blows on the fins. Without cooling these new processors they could literally catch on fire!

Many different types of designs are always made and some are more efficient then others. Some are hugh some are small, but the current trend is a "V type" which has the fins shaped like a V.

Obviously Air flow is the key to a cool case, you want air to easily go in, and go out, and you want the air to travel a wide area of the case to avoid having sections that never get an air change. Remember heat rises, so you want a low intake (cooler air is going in) and a high exhaust (hot air is going out).

A simplified look at Basic PC Case Cooling.

Image courtesy of www.formfactors.org

PC Cases can become cluttered with all those cables, wires, hard drives, cdrom's, floppy divers, sound cards, video cards network modem cards, light fans, dust balls, cat hair, dog hair, carpet pieces, old food, ect... This can prevent proper cooling as it restricts air flow.

The first thing you need to do is clean it out, get all that junk, dust, cat hair, fur balls, out of there. Clean the fan(s). I like to use isoprophy alocohal and a tightly wrapped Q-tip to clean the fan. This way you don't have to physically take them out. (remember to unplug the computer before cleaning). I also use compressed air to blow all that unwanted dust, hair out.

You might be tempted to stick a vacuum-cleaner hose inside and suck out the dust. Don't. Vacuums create static electricity, which is deadly to sensitive electronic components. On that same note, don't be tempted to reverse the flow of your vacuum and blow the dust out of the computer. The dust inside a household vacuum can be harmful to your health, and you'll be spreading it all over your PC. Also, you risk blowing out sizable particles, which could physically damage internal components, especially if you're using a workshop vacuum.

The beauty of compressed air is that it's clean and particle-free. Before you start blasting, unplug your computer and take it outside -- or at least to your garage. Now, working from the top down, blow out all that dust. (Put on a dust mask, unless you want a face full of grime.) As with the fans, be sure to spray air in short bursts, keeping the can upright and the tube at least a couple of inches from the hardware.

Once you have the case clean, look at the air flow, move some cables, wire out of the way (I use those plastic ties to tie them away from the fans). Make sure these is unrestricted flow from the front of the PC to the rear where air will exit. In most computer enclosures, the prime space-wasting culprits are big, flat IDE ribbon cables. To keep things neat and orderly inside your PC, consider replacing these old-style cables with modern, round ones. Round IDE cables help increase airflow and reduce cable clutter.

Example of an uncluttered case:

Adding additional fans are a good idea. However, placement of those fans are crucial to proper air flow.

Most PC Tower cases have places to add additional cooling fans. Example:

So where should you put the fans to achieve the proper cooling?

Cooling fans come in many different sizes: 40mm, 60mm, 80mm, 120mm and many different speeds: 1500 rpm up to above 2500 rpm and different amperage.

For an example AcoustiFans from Acousti Products come in various sizes including 80mm, 92mm and 120mm.

If you are modifying your own case or adding fans, you will want to ensure that air flows over the right components. To get a strong airflow, ensure that air can get to the fan. Many times computer cases provide a grate which you mount in front of the fan as pictured above. Although using a fan up against this grate will produce air flow, I would recommend, if you are handy, to cut out to get the maximum flow from your fan. Doing this step alone can double the CFM you recieve from the fan.

When placing a fan in the front of the PC case remember cool air does not rise, the fan at the bottom of the case will not do a whole lot unless you point it upward toward the processor and video card. This can be done by using some washers behind the fan. You only need a slight angle to ensure the air is flowing upward toward the CPU.

Remember a spacious, well laid-out case is a critical part of proper system cooling. Small cases require components to be packed close together, which worsens cooling in two ways. First, air flow through the case is reduced because it is blocked by the components. Second, the parts are closer together so there is less space for heat to radiate away from the devices that are generating it.

You can also insert a "Blow Hole" much like on a whale, you put an exhaust fan at the top of your case. Hot air rises so this fan is effective at creating a vacuum at the top of your case, thus removing hot air that is not sucked out by the exhaust fans.

A good page showing you how is HERE

One of the items now available for cooling is called a "Chill Vent", there are several manufacures of these as an example:

http://koolsolutions.net/index.htm

A good page for fans is HERE and Air Flow Unit Conversion HERE

For a GOOD CPU FAN read THIS before you go out and invest.

So you say after all this what is the optimal cooling for a PC CASE!

For the average PC, not used for gaming, I would recommend at a minimum:

1 fan in the front of the case bringing air in

1 fan in the back of the case taking air out

A good processor heatsink and fan

These two fans along with your processor and power supply fan should be adequate for most pc cases.