During the 1980s and early 1990s, when the PC was just starting to invade homes in America, users did not have to worry about selecting a video connector for their computer because there was really only one practical choice – Video Graphics Array, or VGA. Video card and monitor manufacturers introduced the Super VGA standard relatively soon afterward, but the connector was still the same. Because early computers supported only analog video signals, there was not much need to stray from the tried-and-true VGA interface. However, since the introduction of digital video for the PC in the late 1990s, manufacturers have introduced several other connection interfaces for connecting computers to a monitor or even a television.
Video Graphics Array (VGA)
When released in 1981, the original IBM PC used a CGA, or Color Graphics Adapter, to display texts in 16 colors at resolutions up to 80x25 pixels. After only a couple of years, IBM replaced the CGA standard with EGA (Extended Graphics Adapter) and subsequently with the Video Graphics Array, which is still the video connector most commonly found in computers used today. VGA is known as an array rather than an adapter because it was the first video system based on a single chip design instead of using dozens of individual chips to process video signals. Chips used on early VGA cards were the first graphics processing units and laid the groundwork for the ultra-fast GPUs used on today’s modern 3D graphics cards. VGA connectors use a 15-pin connector in an enclosure known as a D-Sub, D-Shell or HD 15 casing. VGA transfers video signal data using analog signals only and support a maximum hardware resolution of up to 800 x 600 pixels at 70Hz. While VGA connectors can output much higher HD or widescreen resolutions, Windows must use software interpolation to bypass the hardware limit of 800 x 600 pixels. Depending on the speed of your video card’s GPU, this can decrease video performance slightly in fast action games or CAD programs, but has no noticeable difference in most other desktop applications.
Digital Video Interface (DVI)
Introduced in 1991, DVI was the first major video connector type to see widespread integration in PCs since VGA hit the market in 1987. There are actually six types of DVI connector interfaces. Some support analog only connections, some only digital connections. Two types, DVI-I and P&D, support both analog and digital connections. Early DVI-capable video cards usually supported either DVI-A (analog only) or DVI-D (digital only) connectors, but not both. Newer video cards, though, usually have a DVI-I connector that supports both output formats. DVI-I transmits analog or digital video signals based on the type of monitor connected to the video-out connector on the video card or motherboard. DVI-I connectors have 18 round pins (three rows of six) and two flat blade connectors. DVI connectors were the first to support true HD resolutions (1920 x 1080 pixels) without software interpolation. DVI connectors support hardware-based resolutions up to 2048 x 1536 pixels at 60 frames per second, making it a more ideal connection type if you want to play fast-paced 3D action games without ghosting or screen lag.
High-Definition Multimedia Interface (HDMI)
Introduced in 2002, HDMI is the connection of choice for most high-end Blu-ray or DVD players and large-screen televisions. HDMI is a true digital connection type that supports both 720p/i (1280 x 720 pixel) and 1080p/I (1920 x 1080 pixels) HD resolution formats. An HDMI Type A connector -- the kind usually found on computer monitors and video cards -- resembles a large USB plug and carries both audio and video signals over the same cable, removing the need to connect speaker wires for monitors with an HDMI port and integrated speakers. In July 2012, version HDMI 1.4 was released, which added Fast Ethernet support to the connection. However, only a few monitors offered an integrated network port for using the feature, as it increased production costs for the display and motherboard-integrated or discrete network adapters generally provide much better network performance. While HDMI is an excellent connector medium for set-top video players and televisions, it is not as suitable for many PC users that require resolutions higher than 1920 x 1080 or need the ultra-fast refresh rates for 3D games or CAD applications that DVI offers.
DisplayPort is a royalty-free specification introduced by VESA in 2006 and is the fastest type of video connector type available on PCs. Similar in design to HDMI, VESA designed the DisplayPort specification specifically with computers and video cards in mind. Early adopters of DisplayPort were manufacturers of high-end video cards aimed at CAD operators and 3D-gaming enthusiasts because of the high-cost of the connectors and fast video bandwidth specifications. In 2008, VESA released version 1.2 of DisplayPort, which increased bandwidth features for the connector in many ways. Video cards or computers with a DisplayPort 1.2 connector support resolutions up to 3840 x 2400 pixels on a single monitor, resolutions up 2560 x 1600 pixels in a dual-monitor setup and can transmit video, Ethernet and USB data over a single cable at speeds up to 720Mbps to deliver true HD video at a blistering 120 frames per second. DisplayPort uses a connector very similar in appearance to HDMI, which you can find on some high-end video cards as well as integrated adapters on more expensive motherboards.
- Hardware Secrets: Video Connectors Tutorial
- PCMag.com Encyclopedia: Definition of VGA
- PCMag.com Encyclopedia: Definition of DVI
- PCMag.com: Definition of HDMI
- PCMag.com: Definition of DisplayPort
- PC Hardware: Video and Graphics Cards Explained
- Digital Connection: Video Cable Selector and Usage Guide
- Cables2Go: About Video
- Comstock Images/Comstock/Getty Images