CompTIA A+® Certification All-In-One For Dummies®, 2nd Edition

1.2. Identifying the Types of Motherboards

Now that you understand some of the major components of the motherboard (system board), it is important to mention the different motherboard form factors. A motherboard form factor just describes the dimensions of the motherboard and the layout of the motherboard components.

You need to understand the different motherboard form factors because you can't just take any motherboard and place it in a computer case. For example, you must put a full AT motherboard in a full AT case, a Baby AT board in a Baby AT case, and an ATX board in an ATX case. Figure 1-29 shows the three major types of motherboards to give you an idea of size and shape differences between the three types.

Figure 1.29. Looking at different motherboard form factors.

1.2.1. Full AT

The full AT motherboard — 12″ wide and 11″ long — is easily recognized by the fact that it has only a keyboard connector on the back of the motherboard and that it contains no other I/O ports.

The full AT suffers from a problem with accessing some items on the motherboard because the drive bays hang over the motherboard. This configuration makes installing and troubleshooting motherboard components very difficult.

Another problem with the layout of the full AT board is that the expansion cards, after having been inserted into the systems, cover the processor. This situation leads to cooling ...