3.3 The Computer Case and Power Supply
3.3.2 Desktops
Some of the more familiar case styles found are the desktop designs. Desktop units are designed to sit horizontally on the desktop. Note that the first IBM computers, the original IBM-PC, XT, and AT designs, use this case style. Most desktop cases today come either the slim-line or regular size.

There are two important considerations in choosing a desktop case style for a computer:

  • Available desktop space – Generally the computer would have to share the desktop with the monitor and other peripherals, so space must be allowed. Avoid buying the slim-line because these are generally small and designed for business environments. They have little room for expansion.
  • Form factor – Cases come in different form factors. As mentioned previously, the form factor simply describes the general layout of the computer case, the positioning of the slots in the case, and the type of motherboard the case will accommodate. The baby AT form factor, which accommodates the baby AT motherboard, has been the most popular for the past few years. However, the newest form factor, and the one most often encountered, is the ATX. It accommodates the ATX motherboard, which has integrated I/O ports and is designed for easier access to the common components as well as better airflow. If selecting a desktop case, choose the ATX form factor.