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If you're looking for a new video board, you'll have a lot of choices. In addition to resolution, color-depth and memory issues, there are a number of things to look for:
In computers the term "bus" refers to the wiring scheme used to transmit information to and from the microprocessor. You'll have to know what kind of bus your computer uses for video to determine the right adapter for your machine.
AGP Bus. Short for Accelerated Graphics Port , an interface specification developed by Intel Corporation. AGP is based on PCI, but is designed especially for the throughput demands of 3-D graphics. Rather than using the PCI bus for graphics data, AGP introduces a dedicated point-to-point channel so that the graphics controller can directly access main memory. The AGP channel is 32 bits wide and runs at 66 MHz
PCI Bus. The Peripheral Components Interconnect bus is the second option for graphics card expansion. If your computer has an open PCI expansion slot, make sure you get a PCI video board. You'll get the best performance.
PCI Express. PCI Express is the latest interface for connecting a graphics card to a computer system, and it is the successor to AGP in terms of gaming graphics performance. A recent Tech Tip focused on PCIe and detailed the significant performance increases and flexible configurations available with PCI Express graphics cards.
It's hard for your computer to produce full-motion video. That's because even a relatively low-resolution (640 x 480 pixels and 256-color) screen requires half a megabyte of memory. When you consider that normal broadcast video requires the screen to be redrawn 30 times per second, you can see that a lot of computing horsepower is required.
To reduce the load on your computer, the Motion Picture Experts Group (MPEG) has developed a scheme to compress full-motion video data. The decompression can be handled by software, which still requires some serious work by your processor, or it can be handled by special hardware in your video adapter. The hardware solution is much faster. Many newer video boards have built-in MPEG capability. If you're interested in multimedia applications, it's a good idea to buy a computer or video board that has MPEG-compatible hardware.
If you're interested in computer-assisted design or just getting the most out of the latest games, get a video board that's optimized to render three-dimensional objects quickly. This may require downloading and installing a 3D accelerator program like DirectX/Direct3D or OpenGL.
If your computer's original video adapter was built into the motherboard, you may have to disable it before you can install a new video board. Otherwise, your computer may not be able to figure out which one to use. Often, this is just a matter disabling the onboard card from the hardware manager of your OS. Look in the manual that came with your computer (it's usually with all that boring technical stuff in the back) or call the manufacturer's technical support line if you're not sure.
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