Free computer hardware tutorials

Computer Video Tutorial

On the "Sound" page I talked about how advancements in audio technology make our PC experience enjoyable. Well, the same can be said about good video. People love a good, clear picture, whether it's on a television or a monitor. When it comes to computers, graphics card technology has come a long way and is the main factor that determines the type of image quality and performance you will see.

Like the sound card, all PCs today come with built-in video on the motherboard, or you can install your own or have one installed if you don't want to use the on-board graphics. Most of them contain more advanced features than what's on a motherboard.

Video Card

Current video cards are designed for PCI Express slots because they provide excellent speed that is needed for today's video games and other applications that require superior video quality. Before PCI Express, AGP (Accelerated Graphics Port) was the main slot used for video cards, but is now too slow for today's standards. AGP slots can still be found on some motherboards, but they are practically obsolete.

Video cards contain their own processor (called a GPU for Graphics Processing Unit), memory, and BIOS. The GPU carries out all the difficult math calculations to produce images, especially real life-like 3D images like those in video games. They generate lots of heat like a computer CPU and also require a heat sink or fan on them. When it comes to memory, adapters use a type of DDR called GDDR (the "G" is for graphical) to distinguish it from regular DDR memory used by the PC. Most today support GDDR3, GDDR4, or GDDR5. These differ in terms of bandwidth (the amount of data transmitted) and power usage.

The type of processor technology and amount of memory are two key factors determining performance. However, the kind of port a card has also plays a role in the clarity of the image.

Nvidia, ATI (ATI was bought out by AMD) and Intel are the main competing graphics processor producing companies. Right now Intel only produces onboard graphics. Nvidia and ATI have developed graphics card technology primarily for games - SLI and Crossfire.

For those who are serious about games, SLI technology and Crossfire give you the ability to use multiple video cards in one system for ultimate performance. Let's take a look at a few features from both.

  • SLI technology was developed by Nvidia
  • You must have a motherboard with at least two PCI Express x 16 slots and an SLI MCP (media and communications processor). Boards with these on them are termed SLI-Ready.
  • You need an SLI connector for joining the two cards (although not necessary with some mainstream cards)
  • It can output in analog or digital
  • You must have an SLI-Ready power supply
  • You must use Nvidia video cards with the same GPU model
  • Supports Intel and AMD CPUs
  • Supports 32 & 64 bit versions of Windows XP, Vista, 7, & Linux
  • Designed to support two monitors but can run multiple monitors (up to 6) using GeForce 8 series cards & later with Win Vista or Win 7 OS only
  • 3-way SLI is also available allowing you to utilize three GPUs with even better image quality and a resolution up to 2560 x 1600. A 3-way connector is required and a motherboard with at least three PCIe slots.
  • Quad SLI has come on the scene too, meaning four graphics processors are supported, in other words, two cards with two GPUs on each. A Quad SLI motherboard has to have extra spacing between the PCIe slots.
  • Developed by ATI
  • Uses ATI Radeon cards
  • Must have a Crossfire-Ready motherboard with PCIe slots
  • Supports up to five monitors when not in Crossfire mode
  • Uses a DVI cable to join cards
  • Supports a mode called Super AA for high-quality images
Since both are similar and offer excellent quality, when choosing a video card, you may want to consider other factors such as price.

DirectX Drivers & Other APIs:
For multimedia in general and especially games, Microsoft uses DirectX drivers. DirectX is an application programming interface (API) that lets programmers write software to control multimedia hardware. The part that deals with graphics is called DirectX 3D. It has been around for a long time with version 11 being the latest release and is supported by Windows 7 and also Vista.

OpenGL is an API for non-Windows and Windows systems alike. OpenCL is the latest standard but is used for non-graphics intense jobs like performing video conversions. Nvidia released this driver for the public in late Sept. 2009 and it supports Win XP, Vista, 7 and Mac's Snow Leopard.

Below are the main monitor connectors you'll see when looking for a video card:

VGA - VGA monitor connectors have been around for a long, long time. They are usually blue and use a 15-pin cable for connecting CRT monitors(although some flat panel monitors have a VGA connector). VGA is analog and provides a maximum display resolution of 800 x 600 pixels. Although digital video technology has replaced analog, a number of graphics cards still come with a VGA port.

S-Video (Separate Video) - An S-Video port is a small, round, black connector that lets you attach a monitor or TV. It is sometimes labeled TV Out. With S-video, brightness and color are transmitted along separate wires (hence the term Separate Video), reducing interference with each other and thus providing a better image. S-Video is analog.

DVI (Digital Visual Interface) - The DVI monitor connector provides an all-digital signal from the PC to the display and is on flat-panel monitors. Since there is no digital to analog conversion process as with CRT displays, there is no loss of image quality. DVI uses either a single link or double link cable. A single link cable can support a max 1920 x 1080 pixel image and a dual link 2048 x 1536 image. DVI carries no audio.

HDMI (High Definition Multimedia Interface) - HDMI is the latest digital technology and is replacing DVI. Unlike DVI, HDMI delivers audio as well as video on one cable. In addition, video data is transmitted uncompressed, meaning it is not "shrunk" into a smaller file before being sent over the internet, resulting in even better quality images. The connector kind of resembles a USB port, but is more trapezoidal in shape.

Video Card

LCD Monitors:
A good monitor is an important part to any system. We all love those clear, sharp images. LCD computer monitors are what's sold today. They are lightweight and easy to carry - a far cry from the old heavy and bulky CRTs. But when it comes time to buy one, how do you select? As with just about any product, there are so many choices. The main two considerations that first come to mind are screen size and resolution. Most screens now range from 17 inches to over 25 inches, and screen size is always measured diagonally across the viewing area only. With resolution, the higher the better. Resolution is how many pixels that are on the screen. The more pixels, the sharper the image. It is listed by the number of pixels across the screen followed by the number of rows. For example, the minimum resolution for a widescreen HD monitor (or TV) is 1280 x 720. 1280 is the number of pixels in each row and 720 is the number of rows. Multiplying these numbers gives the total number of pixels.

Another feature that affects clarity is contrast ratio. It is the ratio of the brightest white to the darkest black. The greater the contrast, the clearer the image. Popular ratios are 500:1 and 800:1, although you sometimes see 1000:1. A monitor with a contrast ratio of 800:1 means that the brightest point is 800 times as bright as the darkest point.

Additional Features:
Viewing Angle: If you move to the left or right of the screen (or top or bottom), you'll notice that at some point the picture begins to fade out. The horizontal and vertical viewing angle is the degree you can move from the center of the screen before the image fades. The minimum is usually about 120 degrees.

Brightness (Luminance): Amount of light produced, measured in nits or candelas per square meter (cd/m2). 1 nit is 1 candela per square meter.

Response Time: How fast pixels change colors, measured in milliseconds (ms). It has a direct impact on the ghosting effect. Ghosting is when a moving object leaves a trail. If playing games or viewing anything with fast motion, try to get a monitor with 16ms or faster response time.

Tilt/Swivel: In addition to tilting, many LCD monitors can now swivel, and some even come with height adjustment.

Cleaning Your Monitor:
When cleaning a LCD monitor use a lint-free cloth. There are cleaners and cloths you can buy that are specially made for LCDs. Do not apply the cleaner directly to the screen. Always spray it on the cloth. Wait until the screen is completely dry before turning it back on.

When buying a monitor at a local store, it's a little easier to choose because you can view the products and performance with your own eyes. But if purchasing online, read product reviews on retail sites or visit sites that compare the prices and performance of various products.

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