Figure 1: Airflow inside computer

Correct Airflow

In the normal way of things, very little or no attention at all is paid to the choice of a case for housing a computer. However, nowadays processors are heating up ever more, so choosing the right case is critical for avoiding computer overheating.

Nowadays, overheating is not only due to the computer's processor: the motherboard's chipset and video card's video processor are also responsible for heating the air inside the case.

The typical symptom an overheating computer is when it locks (freezes up) too much and issues errors of General Protection Failure ("This program has carried out an illegal operation and will shut down") and the infamous "blue screen of death". If you remove the case's cover and, with the computer open, the computer stops being troublesome, the problem is overheating. Note that these symptoms also turn up in other maintenance situations, i. e., they do not necessarily mean that the computer is overheating.

Usually the case comes with its power supply installed. Few people are aware of it, but the power supply plays a basic role in cooling the computer's innards. To understand this, you must understand how the air circulates in a case. You must have noticed that every power supply has a fan. This fan should always be operating in the exhaust direction, that is, blowing towards the outside, expelling hot air form inside to outside the case.

Look at Figure 1 to get a better picture. As hot air has a natural trend to move upwards, the hot air produced by the computer automatically flows to the upper part of the case. The power supply's fan then draws out this hot air, thus providing proper computer ventilation. Cool air automatically comes in through the case's front via a suitable slot placed under the space intended for the hard disk.

Figure 2: Detail of the space between the power supply and the system processor.

The power supply must have slots on its side in order to let hot air get out of the case and prevent computer overheating. The precise location of such slots will depend on the case size, since depending on the size of the case and power supply the power supply can be located in above, in front or besides the CPU – which is the main heat source inside the PC. With a bit of common sense, it is easy to see where these slots should be located.

Looking closer at the computer shown on Figure 1 (see its close up on Figure 2) we can conclude that its power supply is correctly sized for its case. Note that the slots on the power supply are in the proper path for expelling hot air produced by the computer's processor and other internal components, i. e., the position of the power supply does not hamper exhausting hot air from the processor and the slots are practically in front of the processor in order to allow hot air to flow correctly out of the computer.