How Graphics Cards Work computer.howstuffworks.com

The images you see on your computer monitor are made of tiny dots called pixels. At most common resolution settings, a screen displays more than 2 million pixels, and the computer has to decide what to do with each one in order to create an image. To do this, it needs a translator — something to take binary data from the CPU and turn it into a picture you can see. This translator is known as a graphics processor, or GPU.