The Purpose of a Graphics Cardby David Nield
The purpose of a graphics card is to control the visual output of your computer. The more powerful a graphics card is, the better the graphics performance of the computer as a whole. High-end graphics cards are particularly useful for gaming and video editing, as well as other visually demanding tasks, such as manipulating large images or running multiple applications on screen at once.
How a Graphics Card Works
A graphics card takes the visual output instructions from an application, interpreting and rendering them correctly, and then sending them to a monitor or other display. Many motherboards now come with graphics capabilities built into them, though these onboard chipsets are usually less powerful than dedicated cards. This is why computers with integrated motherboard graphics (like low-end laptops or netbooks) have poorer graphics performance than those with one or two graphics cards installed.
Graphics Card Specifications
Graphics cards come with a processor and onboard memory which are usually listed prominently in the card's specifications. These two components work in the same way as the CPU and RAM do on a motherboard: the processor handles calculations relating to graphics output, while the memory enables more data to be accessed at any one time. A card with a faster processor and more memory is therefore able to display a high-end game at a faster frame rate and a higher display resolution, because it can calculate new frames more quickly and hold more pixels in its memory.
Choosing a Graphics Card
Many graphics cards are available on the market with new models appearing on a regular basis. Due to the fast pace at which graphics card technology moves, it is often possible to pick up nearly-new cards for a decent price. The very latest and most expensive cards produce the best performance, but the difference is only noticeable when working with large amounts of video or running the latest games at the highest resolutions. It's important to check compatibility with your motherboard when choosing a graphics card and some boards enable you to run two graphics cards in tandem for extra performance.
Inputs and Outputs
The PCI-Express slot on a motherboard is used to install most modern graphics cards, though older machines may use a PCI (Peripheral Component Interconnect) or AGP (Advanced Graphics Port) slot instead. Cards come with a variety of outputs to match different monitors and devices. Many graphics cards now offer HDMI (High-Definition Multimedia Interface) outputs, though the older DVI (Digital Visual Interface) and VGA (Video Graphics Array) connections are still in existence.
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