Video adapters are available in AGP, PCI, and other older interfaces.

Accelerated Graphics Port (AGP)

AGP represents an advancement over previous video interfaces. It allows for more efficient transfer of data between the chipset and the graphics controller. There have been three different connectors used for AGP. These are designed so that only the correct card can be inserted into a given slot. Each connector represents a different standard that includes a different signal voltage and other parameters.

PCI Video Cards

PCI video cards are rarely used for primary video adapters anymore; they are almost always used when built-in video fails or to feed video to second monitors. In the late 1990s, however, there were systems in which the video did come in PCI.

DVI Video

DVI video is becoming more popular, especially as digital flat-panel monitors become more commonplace. DVI video is available mainly in AGP video cards and as built-in video. DVI video can be better and faster than analog video. A computer's VGA port outputs analog video that the video adapter has converted from digital using a Random Access Memory Digital-to-Analog Converter (RAMDAC) chip. All flat-panel monitors are digital, but those with VGA connectors have to convert the analog signal back to digital. Video that has been converted from digital to analog and back to digital again loses some quality. Therefore, it is best to use a digital flat panel monitor with a DVI output. Early digital flat panel monitors used oddball video connectors: the MDR-20 and the Plug & Display connector. The DVI connectors shown in tutorial 3 aren't compatible with these, but a few adapters are available. Search the Internet to find them.

For more information on DVI, see tutorial 3, or go to matrox.com/mga/ products/tech_info/dvi_backgrounder.cfm.

Older Video Interfaces

The only other interfaces you could run into on PCs built since the mid-1990s are ISA, which fit into ISA slots, and VESA Local (VL) Bus. VL Bus adapters fit only into VL Bus motherboard slots. These rather long slots are found only on PCs from the mid-1990s.

Speed

Video speed comes from the type of AGP port, the chipset, the RAMDAC chip, and the type and amount of video memory. With applications that are used to manipulate images, greater speed and memory amount allows for much faster loading and manipulation of images. Moreover, the faster the RAMDAC chip, the faster the refresh rate. We discuss refresh rates later in this tutorial.

Removal and Installation of Video Adapters

Video adapters are removed and installed similarly to other expansion cards. AGP slots might have optional retention clips to hold them in place (retention clips are covered later in this tutorial).

To upgrade a video driver, go to Add/Remove Programs in Control Panel and uninstall the drivers, if present. If prompted to restart the computer, say No, and shut down instead. Remove the existing video card and install the new one, following the manufacturer's directions exactly. For onboard video, follow the same instructions, obviously omitting the step of removing the video card. Install the new card, start the computer, and go into the BIOS and look for a setting to disable onboard video. If there is such a setting, disable it. Then, finish booting the computer to test the new video.

Video chipset maker nVidia® (nvidia.com) provides a single set of drivers, called Detonator™, which will work with any card with an nVidia chipset, regardless of the card's manufacturer. ATI (atitech.com) has a similar driver set called Catalyst™, although it doesn't cover all ATI chip cards.

Bent Pins

If, in a VGA connector, one pin is not making contact with the corresponding terminal in the socket, the video will be degraded. It is common to be missing one color in the event this happens. Use a small probe such as a thick sewing needle, needle-nosed pliers, tweezers, or hemostats to try to gently straighten the pin. Know, however, that such a pin has been weakened and runs the risk of breaking off. In the event that the cable is permanently attached to the monitor, it is recommended to attach a VGA extension cable and never remove it. This protects the pin from breaking off, which would require an expensive monitor repair or replacement, and also protects the video port from getting a pin fragment stuck in it, which would also require replacement.

Troubleshooting Specialty Video Devices
For video capture devices (video cards that include composite video inputs for connection to VCRs and older video cameras, or cards with FireWire ports that connect to digital video cameras), and video cards with TV outputs, a common problem is that Windows installs the wrong driver. Uninstall the existing driver and follow the manufacturer's instructions to install the correct driver.

Monitor Settings

Today's CRT monitors (those with television-like picture tubes) can handle the highest settings computer users are likely to want to use. If you run into a situation, however, in which an old monitor is displaying unusable video, it is possible that the Windows video settings exceed the capabilities of the monitor. You will have to diagnose the source of the problem. If you are able to read the text that appears on screen as the system is starting but the video becomes distorted and unreadable once Windows starts up, then the settings are most likely too high for the monitor. If the image is distorted from the moment you start up the computer, then it is possibly a video adapter issue. If it is the former, you will have to start Windows in Safe Mode, which will give you basic settings that almost all monitors will work with. While in Safe Mode, set the Display Properties to a lower setting and restart Windows. At this point, you might very well decide to get a new monitor that can display higher settings rather than live with a low resolution. You can try to find the monitor's specifications on the Web and set the Display Properties accordingly. If you can't find this information, which is possible, you'll have to try lower settings until you find a combination that works.

The monitor itself will have settings for shape and size of the picture, brightness and contrast, and others. In addition, virtually all monitors manufactured for the last several years have an energy saving system. When the video signal from the computer stops, the monitor goes into a low-power state, and the power indicator light begins to blink or turns from green to orange. Some monitors, however, show a test pattern or no-video message in certain circumstances such as when the power comes back on after a failure and the computer is still off.

Refresh Rate

A monitor (or television, for that matter) produces a picture by having an electron beam scan a grid of microscopic light-emitting elements. The refresh rate is the rate at which the beam scans all the elements—the entire screen—once. The rate is expressed in Hertz (Hz), which means cycles per second, so that a rate of 60 Hz means that the electron beam scans the screen 60 times every second. Rates that are too low have noticeable flicker. If the rate is set too high for a given monitor, the video can be unusable and the monitor can be damaged. The higher the refresh rate, the less apparent the flicker will be. Rates of 70 Hz or higher should provide flicker-free video for most people. The refresh rate should be set only as high as necessary to minimize flicker—higher rates, even if all the components support it, can cause other problems such as reduced contrast.

Network Adapters (Network Cards, Network Boards, Network Interface Cards, NICs, Ethernet Adapters)
Considering how complicated networking can be, network adapters are rather simple. They are among the easiest devices to install; simply follow the manufacturer's directions. Cards made by 3Com and Intel are often installed automatically by Windows. Others, including external USB models, require driver disks, but are still easy to get up and running.