Learn about the different types of dual-head ATI graphics cards.
The vast majority of modern discrete video cards use a system of video output called dual-head. This means that the video card has multiple video-out jacks, allowing a desktop computer to use two or more display devices at a time. Video ports and configurations come in a variety of packages on ATI/AMD hardware, depending upon which graphics card you buy.
What is a Dual-Head Graphics Card?
The dual-head system allows two or more monitors (or televisions or projectors) to be plugged into a desktop computer at the same time. This allows users to either mirror the computer desktop across multiple monitors or expand the desktop into a much larger dual-monitor workspace. A discrete graphics card is necessary for a multiple monitor setup -- the integrated graphics processor on most desktop motherboards is insufficient. Multiple monitor workstations are popular in the graphic arts, financial and software development fields, as well as among general computer enthusiasts.
Standard Dual-Head Cards
Nearly all modern graphics cards feature at least two video-out ports, but the type of ports and their combination can vary depending by model. Generally, cheaper budget cards (starting at $50 or less) feature one newer DVI port and one older VGA port. This is meant to allow easy access for older monitors, which may only feature a VGA-in jack. More expensive enthusiast cards (starting at around $175) feature two DVI ports for an all-digital multiple monitor system. If you need to use an older monitor that does not feature a DVI port, these cards include a DVI-VGA adapter in their retail packaging.
Non-Standard Dual-Head Cards
For several years, graphics cards have featured a more diverse range of video-out ports to cater to multimedia consumers. Most new cards feature at least one HDMI port for easy attachment to an HDTV. Cards from some manufacturers may also use S-Video (for older televisions,) component video, DisplayPort (for Apple monitors and other high-end equipment,) or the smaller mini-HDMI port. These ports are usually in addition to a standard DVI/VGA or dual DVI port setup, but only two monitors or displays may be used at one time.
Enthusiast Cards and Multi-Card Setups
The new Eyefinity technology by AMD, which acquired the ATI brand, allows a single high-end graphics card to drive as many as six monitors at once. These cards are very expensive and require new DisplayPort-enabled monitors. If your motherboard features two or more PCI Express card slots, you can use multiple graphics cards to attach three or more monitors to your computer at once. Compatible motherboards can also use ATI's Crossfire technology to combine the processing power of two or more cards for enhanced graphics in video games.
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