Overclocking a graphics card, whether through software, the basic input and output services (BIOS) or with hardware switches, can help to increase performance, but also can damage the card beyond repair. The main benefit of doing this is an increase in speed, although a peripheral benefit might include a better understanding of how the hardware works. The cons depend on how the card is designed and to what extent the overclocking is performed. In general, the largest risk involves bypassing safety mechanisms and causing the circuitry on the graphics card to melt, short or otherwise be destroyed. For a successful overclock, some of the drawbacks can include an increase in the amount of heat that the card outputs and an increase in the amount of power that the graphics card requires to function.
There are several methods that can be used for overclocking a graphics card. Some manufacturers actually provide applications for customers that will go through software channels to change the performance metrics of a card. In most instances, because this software is provided by the manufacturer, this type of overclocking will provide a small to medium increase in performance without putting the hardware at risk. A few manufacturers even sell factory overclocked graphics cards that are safe and operate within the correct parameters.
Third-party applications that are used for overclocking a graphics card can sometimes lead to problems. Changing the intrinsic way in which the card operates means it can be forced to work near the upper boundaries of the hardware, which isn't always how the card was intended to perform. When overclocked in this way, the extra power that is drawn into the card to support the accelerated performance eventually is dissipated as heat. This heat can cause the graphics card to melt or be damaged, or it can reach other nearby components and possibly damage hardware not located on the graphics card.
In the event that overclocking a graphics card succeeds, one of the potential problems that can be faced is a reduction in the accuracy of the card. This can be for many reasons, including a loss of synchronization within its own components, but it can make the card operate in a very unpredictable way. Essentially, calculations might not be made correctly, items in graphical memory might suddenly change or vanish and, occasionally, applications that use the overclocked acceleration might fail. Unlike hardware upgrades that can fix problems such as heat or power consumption, a loss of accuracy usually is only repaired by resetting the hardware to factory settings.