How Graphics Cards Work
By: Jeff Tyson, Tracy V. Wilson & Talon Homer
|
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.
Most entry-level consumer laptops and desktops now come with a secondary GPU built into their main processor, known as integrated graphics. Pro-level or custom machines, however, will often also have space for a dedicated graphics card. The advantage of a graphics card is that it can typically render more complex visuals much faster than an integrated chip.
Advertisement
A graphics card’s job is complex, but its principles and components are easy to understand. In this article, we will look at the basic parts of a video card and what they do. We’ll also examine the factors that work together to make a fast, efficient graphics card.
Think of a computer as a company with its own art department. When people in the company want a piece of artwork, they send a request to the art department. The art department decides how to create the image and then puts it on paper. The end result is that someone’s idea becomes an actual, viewable picture.
A graphics card works along the same principles. The CPU, working in conjunction with software applications, sends information about the image to the graphics card. The graphics card decides how to use the pixels on the screen to create the image. It then sends that information to the monitor through a cable.
Creating an image out of binary data is a demanding process. To make a 3-D image, the graphics card first creates a wire frame out of straight lines. Then, it rasterizes the image (fills in the remaining pixels). It also adds lighting, texture and color. For fast-paced games, the computer has to go through this process about 60 to 120 times per second. Without a graphics card to perform the necessary calculations, the workload would be too much for the computer to handle.
The graphics card accomplishes this task using four main components:
Next, we’ll look at the processor and memory in more detail.
Advertisement
Like a motherboard, a graphics card is a printed circuit board that houses a processor and VRAM. It also has an input/output system (BIOS) chip that stores the card’s settings and performs diagnostics on the memory, input and output at startup.
A graphics card’s processor, called a graphics processing unit (GPU), is similar to a computer’s CPU. A GPU, however, is designed specifically for performing the complex mathematical and geometric calculations that are necessary for graphics rendering. Some of the fastest GPUs have more transistors than the average CPU.
Advertisement
A GPU produces a lot of heat, so it is usually located under a heat sink or a fan. Integrated chips differ slightly, in that they don’t have their own VRAM, and have to pull from the same RAM stockpile as the CPU. This distinction may cause your system to run short on memory while gaming with an integrated GPU.
In addition to its processing power, a GPU uses special programming to help it analyze and use data. AMD and nVidia produce the vast majority of GPUs on the market, and both companies have developed their own enhancements for GPU performance. Today’s video processors can provide:
Each company has also developed specific techniques to help the GPU apply colors, shading, textures and patterns.
As the GPU creates images, it needs somewhere to hold information and completed pictures. It uses the card’s RAM for this purpose, storing data about each pixel, its color and its location on the screen. Part of the VRAM can also act as a frame buffer, meaning that it holds completed images until it is time to display them. Typically, video RAM operates at very high speeds and is dual ported, meaning that the system can read from it and write to it at the same time.
Modern video cards plug into a PCIe x16 expansion slot. Small form-factor computers with integrated graphics, such as laptops and mini desktops, may not come with such a slot. Graphics cards can still be connected, however, using a costly workaround device called an external GPU.
Graphics cards have come a long way since IBM introduced the first one in 1981. Called a Monochrome Display Adapter (MDA), the card provided text-only displays of green or white text on a black screen. Now, both graphics cards and integrated chips can easily send out an HD (1,920 x 1,080 pixel) signal through an HDMI or DisplayPort cable. Standalone cards often put out Ultra HD 4K (3,840 x 2,160) video, with even higher resolutions available on higher spec GPUs.
Advertisement
A top-of-the-line graphics card is easy to spot. It has lots of memory and a fast processor. Often, it’s also more visually appealing than anything else that’s intended to go inside a computer’s case. Lots of high-performance video cards are illustrated or have decorative fans or heat sinks.
But a high-end card provides more power than most people really need. People who use their computers primarily for email, word processing or social media can find all the necessary graphics support on a CPU with integrated graphics. A mid-range card is sufficient for most casual gamers. People who need the power of a high-end card include gaming enthusiasts and people who do lots of 3-D graphic work.
Advertisement
A good overall measurement of a card’s performance is its frame rate, measured in frames per second (FPS). The frame rate describes how many complete images the card can display per second. The human eye can process about 25 frames every second, but fast-action games require a frame rate of at least 60 FPS to provide smooth animation and scrolling. Components of the frame rate are:
The graphics card’s hardware directly affects its speed. These are the hardware specifications that most affect the card’s speed and the units in which they are measured:
The computer’s CPU and motherboard also play a part, since a very fast graphics card can’t compensate for a motherboard’s inability to deliver data quickly. Similarly, the card’s connection to the motherboard and the speed at which it can get instructions from the CPU affect its performance.
For more information on graphics cards and related topics, check out the links below.
Many CPUs have integrated graphics capabilities and function without a separate graphics card. These processors handle 2-D images easily, so they are ideal for productivity and internet applications. Plugging a separate graphics card into one of these systems overrides the onboard graphics functions.
Some people choose to improve their graphics card’s performance by manually setting their clock speed to a higher rate, known as overclocking. People usually overclock their memory, since overclocking the GPU can lead to overheating. While overclocking can lead to better performance, it also voids the manufacturer’s warranty.
Advertisement
Originally Published: Mar 16, 2001
Please copy/paste the following text to properly cite this HowStuffWorks.com article:
Advertisement
`;t.byline_authors_html&&(e+=`By: ${t.byline_authors_html}`),t.byline_authors_html&&t.byline_date_html&&(e+=” | “),t.byline_date_html&&(e+=t.byline_date_html);var i=t.body_html.replaceAll(‘”pt’,'”pt’+t.id+”_”);return e+=`ntttt
How Graphics Cards Work
Research & References of How Graphics Cards Work|A&C Accounting And Tax Services
Source
0 Comments