Whether you are watching your favorite movies over the computer, playing massively multiplayer online games or just simply scanning or uploading pictures over the Internet; the quality and intensity of the graphics you experience is only as good as the video card you have installed.
A graphics card refers to any computer device or program that makes a computer capable of displaying and manipulating pictures. It is a computer component designed to convert the logical representation of visual information into a signal that can be used as input for a display medium. In simple terms, a graphics card is an integrated or expansion card whose main function is to generate output images to a display medium. Display mediums include monitors, LCD (Liquid Crystalline Display) TVs, High Definition (HD) TVs, and projectors.
Most of these graphics cards have added functions which include the following: accelerated rendering of 3D scenes and 2D graphics; video capturing; as TV-tuner adapter; decoding of MPEG-2/MPEG-4; ability to connect multiple monitors; and as TV output. Modern high performance cards are used for PC games purposes some of which are graphically demanding in nature.
Graphics card can be used interchangeably with the terms vide card, video adapter, graphics accelerator, and display adapter.
Components of a Graphics Card
Aside from the motherboard interface and a printed circuit board as a base, modern graphics card contains the following components:
1. Graphics Processing Unit
A Graphics Processing Unit (GPU) is a dedicated processor which is optimized to accelerate graphics. It is designed to perform the fundamental floating-point calculations for rendering 3D graphics and drawing 2D pictures. One of the main characteristics of the GPU is its core clock frequency which translates a 3D image characterized by vertices and lines into a 2D image formed by pixels.
2. Video BIOS
The Video BIOS, also known as the firmware, contains the basic program that controls the graphics card’s operations and instructs the computer and software to interact with the card. The Video BIOS may contain pertinent information such as the Random Access Memory (RAM), memory timing, operating speeds and voltages of the graphics processor.
3. Video Memory
Video memory is used to store many data as well as the screen image, such as the Z-buffer. The Z-buffer manages the depth coordinate in 3D graphics, textures, vertex buffers, and compiled shader programs.
The memory capacity of a modern card ranges from 128MB to 4GB.
The RAMDAC, or Random Access Memory Digital-Analog Converter, is responsible for converting digital signals to analog signals which will be used by a computer display that uses analog inputs such as Cathode Ray Tube (CRT) displays. RAMDAC functions like a RAM chip that regulates the performance of the graphics card.
Graphics cards and the display modules must be connected by some means. The most common connection systems between the two are: the analog-based Video Graphics Array (VGA); digital-based Digital Visual Interface (DVI) such as flat-panel LCD and video projectors; Video In Video Out (VIVO) for connecting televisions, DVD players, video recorders and video game consoles; and High-Definition Multimedia Interface (HDMI) commonly used for game consoles.
6. Power Demand
Nowadays, high performing graphics card tend to consume a large amount of electrical energy. As the processing power of the graphics card increases, so does its demand for electrical power. Despite efforts to make recent CPU and power supply more efficient, the power demands of GPUs still continues to rise, thus making the graphics card the biggest electricity consumer in a computer.
7. Cooling Devices
Since graphics card uses a lot of energy, it is expected that some of this will be converted to heat. If the heat generated is not dissipated into the atmosphere then the graphics card will overheat and in the process be damaged.
To answer this problem, developers have incorporated cooling devices that allows heat to be transfer elsewhere. There are three types of cooling devices employed on a card. These are by using a passive heat sink cooling device, a computer fan, and installing a water block.
Currently there are two type of cards that are available in the market. These are the Integrated type cards and the Expansion type cards.
The Integrated graphics cards are components that are already built-in to the system motherboard. It uses the system’s processor (CPU) and memory to create the actual graphics.
While Integrated cards can process some complex graphics such as 3D images, they have to share the CPU and memory with other programs. If in some instances both the CPU and memory are overloaded, the graphics card is greatly affected in speed. Thus this type of card is useful for applications like word processing and Internet surfing but not much on gaming or other graphic-intensive programs.
The Expansion type card on the other hand operates autonomously and does not depend much on the computer CPU and memory. It is because of this that expansion type graphics card are considered to be the most powerful graphics hardware capable of delivering high-quality 3D graphics. The Expansion type card is further subdivided into two: Discrete video card and Dual video card.
Since the 3D cards for model rendering in art and animation is different from those intended for gaming, specific type of expansion card are used. Despite having similar hardware, their drivers and firmware are optimized for specific tasks. Discrete graphics card are geared towards achieving high performing 3D graphics quality and thus are suitable for gaming, while the Dual graphics card are used for displaying immense files at top speed usually used for high precision rendering.
The graph below sums up all of the different graphics card characteristic and the different application that they can perform. It is a good guideline in selecting a good graphics card for your needs.
If you want to…
Use this card
An entry-level solution for typical office productivity applications, Internet use, relatively small digital images, low-resolution video, simple games and other relatively undemanding applications. Integrated video cards are generally acceptable for:
• Word processing
• Instant messaging
• Small presentations
To tackle complex graphics, applications and gaming. A discrete video card you can handle all the applications an integrated card can handle, plus:
• Complex presentations
• Graphics design
• Financial analysis
• High resolution video
• Video conferences
To process immense graphics files at top speeds for application such as:
• Video editing
• Game creation
• Complex graphics design