Video Card Buying Guide

Video card components

Computer monitors (and regular TV pictures) run about 30 frames per second (fps), while high-end video games and HDTVs require up to 60 fps to really look the way they should. Since the CPU has to run your entire desktop computer or laptop computer, processing over one million pixels 30 or 60 times per second is more than the average motherboard can handle. Video cards add that extra computing boost to the CPU using four principal components:

• Motherboard connections bring in data from the hard drive and electricity from the power supply.
• Memory chips hold the data during processing.
• Graphics processor chips turn digital data into pixel information.
• Monitor connections send pixels to the monitor.

The monitor connections will vary, depending on the target device:

• Video Graphics Adapter: VGA connects to analog monitors, like CRTs.
• Digital Visual Interface: DVI connects to digital display devices like LCD monitors and digital projectors. "DVI-D" are digital-only connectors; "DVI-I" connect to digital or analog monitors.
• S-Video: S-Video is commonly used to connect a PC video card to a television; it is capable of only 480i or 576i resolution.
• High Definition Multimedia Interface: HDMI connects your computer to your HDTV set for downloaded movie or DVD viewing. If you plan to tune your HDTV through your computer, you will probably also need an HDTV tuner.

The video card will have other components, such as a heat sink, which are fairly standard from card to card and assist in its general operation. Some video cards are "dual-head," meaning the card will support two monitors used side by side. If your motherboard has two video card slots, that computer should be able to support up to four computer monitors.

Video card buying tips

First, check out your existing motherboard. If your computer needs are consumer electronics oriented--family photos, Web surfing, word processing, etc.--a factory-installed motherboard with "integrated graphics" (a basic graphics card built into the motherboard) is good enough. If you're a professional or you want high-end graphics, like those in the new video games, buy your new motherboard and new multi-media card at the same time so you're sure they work together properly.

Second, check the specifications. The short answer is the better video card (usually meaning the more expensive video card) has more memory and a faster processor. Specifically, buyers should look at several benchmarks.

• Processor: Current high-end video card processors run 400 to 600MHz. Be careful here, a more expensive video card won't necessarily have a faster processor.
• Memory: 256 MB or 512 MB memory chips are very common; 1 GB or larger is available.
• Maximum Resolution: If your monitor maxes out at 1680x1050 pixels, you don't really need a video card that supports 3840 x 2400 pixels, so don't waste your money.
• Power: New video cards may need more power to process 3-D graphics, which contain far more data than 2-D graphics. Check your video card to see if it pulls more juice than your power supply can put out; you may need a larger juice box.
• Dimensions: Video card sizes do not vary much, they are usually 10 to 12 inches long x 8 to 10 inches wide x about 3 inches thick; you probably won't have any trouble fitting most video cards into most CPUs, but take a look, just to be sure.

Finally, check your budget and spend what you must to get what you need. Remember, there's a big difference between discount computer hardware and cheap computer hardware.

Video card terminology

Expansion card: An expansion card is any card that isn't factory installed. Sound and video cards, additional memory, any upgrades qualify as expansion cards. Video cards plug-n-play directly into the motherboard and utilize two technologies which are not interchangeable. Many motherboards have slots for both card technologies:

Advanced Graphics Port: The earliest AGP video cards, called AGP 1x, included a parallel bus with a data exchange rate of 266MB per second; the newest AGP 8x cards exchange at 2.1GB/sec. Older AGP slots are rated for 1.5 volts, newer slots for 3.3 volts. While still an excellent choice, the AGP video card is the older, lower-end technology that may be entirely replaced in a few years.

Peripheral Component Interconnect: PCI was originally an alternative to AGP, a direct connection between memory and connected devices (meaning video cards aren't the only cards using this technology). Today, they are replacing AGP for many users. The newest incarnation is PCI-Express. A serial bus with 250MB/sec per lane (each lane being like a single parallel bus), PCI-E cards have effective data exchange rates up to 8GB/sec.

Video card care

Your video card should require no maintenance. If it does, take it to a computer repair service; it's not a do-it-yourself project.