What is a graphics card?
A graphics card is responsible for displaying the image you seen on screen. The images are made up by thousands of tiny dots called pixels, on a high resolution screen the graphics card can be displaying millions of pixels.
Originally at the start of the PC revolution the graphics card’s purpose was only to display the image on the screen. The amount of memory present on a graphics card was very small and was not needed to a great extent where the modern cards can have several gigabytes of memory onboard. The modern graphics card is capable of powering breathtaking games, displaying 3D perspectives that show characters leaping out of the screen, running 1080P Full HD video in all its glory and can accelerate non-3D applications using their amazing processing power.
Graphics cards come in two distinct packages. There are integrated solutions such as onboard the motherboard and discreet cards such as those made by Nvidia and AMD ATI. Even the lowest models in the range of add-in cards can outperform onboard solutions often by a magnitude of several times.
What features should I look for in a graphics card?
A modern graphics card has a bewildering list of technologies and features present, it is easiest to work out what you want from a graphics card and then find the features which will give you the best experience.
DirectX: A technology Microsoft has incorporated into Windows that standardises games enabling them to run on graphics cards supporting the same version of DirectX. The game developers make their games to work with DirectX and the graphics card vendors make the cards work with DirectX ensuring compatibility. The latest DirectX is version 11 which currently has the potential to provide the very best graphical images on PC surpassing what is possible on even the most powerful games consoles.
OpenGL: Like DirectX OpenGL is a standard specification for developers to use to ensure compatibility. Unlike DirectX however OpenGL is compatible across multiple operating systems including Windows and Macintosh. OpenGL has decreased in popularity over recent years for games although there are still titles released which make use of OpenGL most notably from the developer Valve. OpenGL is widely used in CAD, virtual reality and scientific applications.
Nvidia 3D Vision: The premier 3D technology on the PC, it has to be experienced to be fully appreciated how revolutionary it really is. A 3D vision capable graphics card with the right monitor and stereoscopic 3D glasses can fundamentally change the way you interact with your PC. With support for over 400 existing PC games, Blu-Ray 3D movies, 3D photographs and streaming the latest sporting events in 3D a 3D vision graphics card delivers the future of the PC experience today. 3D vision works by the Nvidia graphics card being specially programmed to render and display two images instead of one, one for your left eye and one for your right eye. The monitor and 3D glasses work with the Nvidia graphics card so each eye receives its own image. Because each of your eyes receives a separate image, your brain perceives 3D.
Nvidia CUDA & OpenCL: This is a pair of technologies that allows developers to program normal Windows applications to make use of a graphics cards amazing processing power. An application such as a Video encoder can have its performance boosted by up to 1800% by running on a graphics card rather than on the PC’s processor alone.
AMD Radeon Dual Graphics: This is where you combine an AMD APU processor with an AMD Radeon DirectX 11 capable discrete graphics card. The on board graphics on the APU then combine with the graphics card to work together to bring a boost to performance and an overall experience far better than just running the on board or graphics card on its own.
AMD Eyefinity: One of the most impressive technologies currently available on the PC. Allowing the graphics card to run up to 6 screens from one PC you can create amazing setups for work or play. Able to run as either a bank of 6 separate screens or as one SLS display (Single Large Surface), so that the operating system sees it as one combined desktop. In games you can wrap the monitors around you and see to the sides of your vehicle in racing games, see the sky around you on a flight simulator or display a larger battlefield in a strategy game. For work applications Eyefinity has proved popular for people needing to display a lot of information at the same time such as those in the banking sector. If you ever find yourself switching between open programs to get your work done an Eyefinity capable graphics card and monitors may just be the biggest productivity upgrade you could make. Eyefinity is usually found in 3 monitor configurations for gaming and 6 monitor configurations for business uses.
Nvidia SLI (Scalable Link Interface): Nvidia SLI technology enables two Nvidia graphics cards to work together to dynamically increase performance; you can increase the performance of a single card system by up to 90% by adding a secondary card. Ideally you should pair up graphics cards that are the same model from the same manufacturer to ensure compatibility.
AMD Crossfire: AMD’s answer to Nvidia’s SLI technology that enables two compatible ATI cards to run together to increase performance. You can increase the performance of a single card system by up to 85% by adding a secondary card.
Nvidia PhysX: A technology developed by Nvidia which features on most of their graphics card range to enable advanced physics calculations. Experience dynamic effects like blazing explosions, reactive debris, realistic water and lifelike characters. All with higher detail levels than are possible without PhysX.
What do all the numbers mean?
A modern graphics card is one of the most complicated components in a computer. There are many factors that affect the performance of a graphics card that include its raw specifications, software drivers and the operating system the card is run in.
The easiest way of looking at a graphics card is as a mini graphics dedicated computer on one board. If you do this most of the terminology matches up with what you looks for in other individual components and simplifies the task of deciphering the technical specifications.
Graphics Core Processors: The number of cores on the chip, similar to a dual core or quad core CPU but with several hundred slower cores.
Graphics Clock (MHz): Often called the Chip clock or Core Clock. The speed at which the graphics processor runs at. This is the brain of the graphics card that tells everything else what it needs to do.
Processor Clock (MHz): Often called the shader clock. What determines the performance of the card executing the instructions allocated to the graphics card, this is what is responsible for all the modern graphical effects you encounter in games.
Texture Fill Rate: How much raw data the card can display on screen, usually shown as the performance capable over a single second.
Memory Clock: How fast the memory operates on the graphics card
Memory Configuration: The amount of memory the chip was originally designed to operate with, this can change as technology develops to allow the same graphics card to have several different memory capacities available.
Memory Interface Width: How much data can be processed, in bits, every time the memory operates.
Memory Bandwidth: How much data can be passed through the graphics card’s memory, per second.
Microsoft DirectX: Lists the version the card is compatible up to. All DirectX versions are backwards compatible. For example a DirectX 9 game will be compatible with a DirectX 11 graphics card.
OpenGL: Lists the version the card is compatible up to. All OpenGL versions are backwards compatible just like DirectX.
Bus Support: The physical socket on the motherboard that the graphics card is compatible with.
Maximum Resolution: The highest compatible resolution the graphics card can output at, typically larger monitors require higher resolutions.
Display Connectors: The ports on the back of the graphics card that enable you to output to monitors, televisions or projectors.
Dimensions: Some graphics cards can be quite large, the dimensions are provided to assist in ensuring compatibility with certain cases.
Maximum Temperature: The peak temperature the graphics card can operate at before failure.
Maximum Power Draw: The peak draw the graphics card will make on your power supply. The more powerful the graphics card the more power it will draw.
Supplementary Power Connectors: What power connectors need to be on your power supply for it to be compatible with the graphics card.
What are Graphics Card Drivers?
All operating systems and hardware are made to operate with the same basic functions, this ensures when you plug a graphics card into a machine the operating system will display an image. To unlock all the powerful features of a modern graphics card you need to install a driver. This optimises the performance of the operating system for the graphics card you have installed.
The latest drivers can offer over 10,000% performance increases over the standard Windows driver depending on the application. Without exception it is recommended to run the graphics card with the latest driver provided by the manufacturer.
Nvidia and ATI both regularly update their drivers to improve support for the latest games and applications. It is possible through the use of drivers and the optimisations they bring for a graphics card to slowly improve in performance throughout its life as newer drivers are released.
Do I need to upgrade my Power Supply?
A modern graphics card can use upwards of 300W of power, it is important to ensure it gets the power it requires to prevent unnecessary system instability and make sure the lifespan of the graphics card is not reduced.
When looking for a power supply it is important to consider what other components you are running, adding multiple hard drives, a powerful motherboard, processor and sound card can all add up to making your system require a very powerful power supply.
As a rule the recommended power supply for each graphics card listed by the manufacturer takes into consideration the average system a user is likely to pair with the graphics card.
It is always recommended you purchase a high quality power supply from a trusted brand, a low quality unit may not operate close to its rated specifications or only be able to do so for short periods of time. Remember not all power supplies are made equal.