Function and characteristics
The graphics card is a component that either plugs into the motherboard (external graphics card) or integrated within the motherboard (integrated graphics chipset). It manages everything that is visible on your computer screen. It is composed of a GPU; which is a graphics processor (now often equipped with a fan) and a graphics memory dedicated to it.
That looks like the GPU:
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It is important to check its connectivity, that is, how it allows you to connect. They are all equipped with a VGA connector to connect your screen (otherwise the card would be useless), but the newer cards have also other ports allowing you to attach television.
A classic example of connections:

Various prices
It is interesting that the prices are very different. You can find graphics for a few dollars but for a few hundred (the price of a computer). Why is the difference? For video games and video processing that require ever greater performance.
Also note that this market is evolving quickly. So you can buy a graphics card to one year, and next year you will not see it powerful enough for the latest video game release.
In small CPUs, for example netbooks or laptop computers, the graphics card is often replaced by a graphics chip placed directly on the motherboard. This allows saving the space but it is obvious that you can not use this computer to use for graphics intense, only for the office.
To summarize
- The graphics card can connect a monitor to the computer with a VGA connector.
- It is composed of a GPU and graphics memory.
- For video games and everything about the video processing it is important to have a powerful graphics card.
