What Does a Video Card Do?

You probably know that a computer needs a video card to work properly, but what does a video card do? Also known as a graphics card, display adapter, or graphics board, your video card serves as a translator between the computer and what you eventually see on the screen. Without a video card, the data stays as ones and zeroes, and it can't be visualized. 

What Does a Video Card Do?

On the average computer monitor, there are more than a million individual pixels, which can each display a particular color to create complex images. However, computers need a video card to serve as a middleman between the CPU (central processing unit) and the screen. 

Think of the video card as a graphic designer for hire. When the CPU needs something displayed, it sends a request to the video card, which figures out exactly how to visualize the instructions. In this analogy, the pixels serve as the video card's canvas. To make visuals display on the screen, it sends information to the monitor with a cable, such as VGA, S-Video, or DVI. 

When it comes to translating binary data into 3D visuals, the video card must first start with a basic wireframe, fill in the gaps (called "rasterizing"), and then add complex colors, textures, and lighting effects. For optimal performance, this process needs to be repeated about 60 times (called "frames") per second, or the visuals will start to look sluggish.   

What are some essential video card components?


  • Graphics Processing Unit (GPU): Like the CPU on a motherboard, every graphics card has a GPU, which handles the mathematical computations needed to create visuals. The processor can get extremely hot when performing calculations, so it's usually located underneath a fan or heatsink. Some GPUs have additional features, such as full scene anti aliasing, which makes 3D graphics look smoother. 
  • RAM: While the GPU is figuring out how to display images, it needs to store completed information until it's ready to be used. This is where RAM comes in handy, allowing the card to temporarily save pixel data and then quickly access it when the time is right. 
  • Digital-to-Analog Converter (DAC): When the RAM is ready to send pixel data to the monitor, it first passes through a digital-to-analog converter. This translates the digital information into an analog signal, so that the monitor can understand it. Depending on your needs, some video cards contain more than one DAC, so you can have multiple monitors operating simultaneously. 
  • Connections: Finally, the DAC sends the analog signal to the monitor via a cable. If you're using a newer LCD screen, it will be a DVI connection, whereas older CRT monitors typically have a VGA connection.

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