A half height video card is simply a computer video card that is shorter than a standard or full height video card. These cards might be necessary to fit inside a small computer case, or they might be used to help the computer's fan keep the computer cool. Many of these video cards have the same capabilities as standard full height cards; the only difference is its size. A half height video card sometimes is called a low profile video card.
All personal computers (PCs) built since about 1980 contain expansion slots that allow the user to add or enhance functionality. These include, but are not limited to, network cards, modems, serial and parallel adapters and video cards. These cards come in various slot configurations to match what is in the computer, and they come in different sizes, such as half height and full height.
There are several reasons for using a half height video card. The most obvious is to fit the physical constraints of the computer case. Some mini-towers are smaller in stature and must use video cards that are smaller than the standard size.
Another reason to use a smaller video card is to enhance the cooling of the computer by the fan. Full height video cards can constrain the flow of air, especially to other expansion cards that might be behind the video card. A standard video card has a height of about 4 inches (10 cm), and a half height video card typically has a height of about 1.4 inches (3.5 cm).
A video card is part of the standard computer configuration, and almost all computers have video cards built into the motherboard. The reason for adding a second video adapter card might drive the decision between a standard height video card and a half height video card. The most common reason for adding a video card to a system is simply that the original card either stopped functioning or became obsolete. An example of this would be adding a modern monitor to a system that supported only video graphics array (VGA). In these cases, buying and using a cheap video card might be best.
At the other end of the spectrum are users who want to use the computer for advanced gaming. In this case, the video card that came with the computer might be underpowered for the games being played. This can cause problems with resolution and refresh rate, making the games look fuzzy or sluggish. For these users, a professional video card or a gaming video card might be required. The extra power and memory provided by these cards is more than that of a standard video card, so a half height video card might not be feasible.
Another reason for adding a video card is for users who want or need dual displays. This allows the attachment of two monitors to the computer. Often one will be a standard monitor, and the other will be a large flat screen or high-definition (HD) monitor. For these users, a dual monitor video card might be required to give the extra power and throughput required for these advanced uses.