The video card is in charge of controling your video display, also known as a monitor. It is responsible for making decisions for graphical data input and output. The video card in the computer dictates the resolution, refresh rate, and number of colors that are available to your monitor. Also, keep in mind the monitor must support those ranges, if you wish to fully utilize the video card. Some video cards will only plug into a monitor, while others will be able to take input/output from various sources like TVs, VCRs, or even Cable TV.