The computer video card is the device that takes output and interprets it; instructing the monitor on which of the tiny dots on the screen to light up to produce the right graphic image for you to see. In other words, the Video Card, also known as the graphic card, is the graphic powerhouse of your computer that organizes virtual output.

The type of graphic card you have on your system determines the quality of the images you see on your screen. Before we begin on PC problems that may arise when your PC graphics card is faulty, it is important to understand that not all problems listed below are unique to a faulty graphic card.

1. A Dead Screen

A blank screen may be due to a wrong graphic card connection – card not properly fastened to the connector. To solve this problem, shut down the system and check to see that the video card is well connected. Also, inspect the connector pins. A broken or missing pin could breach contact.

2. Loud Noise

The video card has a fan. The more powerful the video card, the larger the fan may be. A failing fan gives out a screeching noise. Cleaning up the fan could help resolve this problem. Another thing to do is to replace the fan if your computer graphics card has a replaceable fan. Otherwise, you may need to replace the graphics card altogether. So at this point, it is wise to get a video card with replaceable fan.

3. Irregular Size of display on the Screen

This is when there is a display but it does not fit properly to your computer screen. To resolve this, check the resolution settings (on the control panel click on display settings). If the problem persists, try to update the graphics card drivers.

4. Wrong Color Display

This could be resolved by merely changing the display resolution. To do this, click on the display settings from the control panel. If this is not of help, update the video card drivers. You can also mess with the color settings on the monitor itself or in the display setting from the control panel

We hope you have found the above troubleshooting tips helpful. These common PC problems often point to a faulty video card. When any of the above occur in a computer, it is very likely that your video card is faulty. However, other failing hardware devices may share one or more of these problems. Therefore, these are not solely unique problems to failing video cards. To identify and eliminate failing hardware, you have to be patient and sometimes lucky.

source: http://www.computertooslow.com/diagnose-video-card-problems.asp

The images you see on your monitor are made of tiny dots called pixels. At most common resolution settings, a screen displays over a million pixels, and the computer has to decide what to do with every one in order to create an image. To do this, it needs a translator — something to take binary data from the CPU and turn it into a picture you can see. Unless a computer has graphics capability built into the motherboard, that translation takes place on the graphics card.

A graphics card’s job is complex, but its principles and components are easy to understand. In this article, we will look at the basic parts of a video card and what they do. We’ll also examine the factors that work together to make a fast, efficient graphics card.

Think of a computer as a company with its own art department. When people in the company want a piece of artwork, they send a request to the art department. The art department decides how to create the image and then puts it on paper. The end result is that someone’s idea becomes an actual, viewable picture.

A graphics card works along the same principles. The CPU, working in conjunction with software applications, sends information about the image to the graphics card. The graphics card decides how to use the pixels on the screen to create the image. It then sends that information to the monitor through a cable. ­

Creating an image out of binary data is a demanding process. To make a 3-D image, the graphics card first creates a wire frame out of straight lines. Then, it rasterizes the image (fills in the remaining pixels). It also adds lighting, texture and color. For fast-paced games, the computer has to go through this process about sixty times per second. Without a graphics card to perform the necessary calculations, the workload would be too much for the computer to handle.

The graphics card accomplishes this task using four main components:

* A motherboard connection for data and power
* A processor to decide what to do with each pixel on the screen
* Memory to hold information about each pixel and to temporarily store completed pictures
* A monitor connection so you can see the final result

The GPU

Like a motherboard, a graphics card is a printed circuit board that houses a processor and RAM. It also has an input/output system (BIOS) chip, which stores the card’s settings and performs diagnostics on the memory, input and output at startup. A graphics card’s processor, called a graphics processing unit (GPU), is similar to a computer’s CPU. A GPU, however, is designed specifically for performing the complex mathematical and geometric calculations that are necessary for graphics rendering. Some of the fastest GPUs have more transistors than the average CPU. A GPU produces a lot of heat, so it is usually located under a heat sink or a fan.

In addition to its processing power, a GPU uses special programming to help it analyze and use data. ATI and nVidia produce the vast majority of GPUs on the market, and both companies have developed their own enhancements for GPU performance. To improve image quality, the processors use:

* Full scene anti aliasing (FSAA), which smoothes the edges of 3-D objects
* Anisotropic filtering (AF), which makes images look crisper

­ Each company has also developed specific techniques to help the GPU apply colors, shading, textures and patterns.

As the GPU creates images, it needs somewhere to hold information and completed pictures. It uses the card’s RAM for this purpose, storing data about each pixel, its color and its location on the screen. Part of the RAM can also act as a frame buffer, meaning that it holds completed images until it is time to display them. Typically, video RAM operates at very high speeds and is dual ported, meaning that the system can read from it and write to it at the same time.

­ The RAM connects directly to the digital-to-analog converter, called the DAC. This converter, also called the RAMDAC, translates the image into an analog signal that the monitor can use. Some cards have multiple RAMDACs, which can improve performance and support more than one monitor.

PCI Connection

Graphics cards connect to the computer through the motherboard. The motherboard supplies power to the card and lets it communicate with the CPU. Newer graphics cards often require more power than the motherboard can provide, so they also have a direct connection to the computer’s power supply.

Connections to the motherboard are usually through one of three interfaces:

* Peripheral component interconnect (PCI)
* Advanced graphics port (AGP)
* PCI Express (PCIe)

PCI Express is the newest of the three and provides the fastest transfer rates between the graphics card and the motherboard. PCIe also supports the use of two graphics cards in the same computer.

Most graphics cards have two monitor connections. Often, one is a DVI connector, which supports LCD screens, and the other is a VGA connector, which supports CRT screens. Some graphics cards have two DVI connectors instead. But that doesn’t rule out using a CRT screen; CRT screens can connect to DVI ports through an adapter. At one time, Apple made monitors that used the proprietary Apple Display Connector (ADC). Although these monitors are still in use, new Apple monitors use a DVI connection.

Most people use only one of their two monitor connections. People who need to use two monitors can purchase a graphics card with dual head capability, which splits the display between the two screens. A computer with two dual head, PCIe-enabled video cards could theoretically support four monitors.
In addition to connections for the motherboard and monitor, some graphics cards have connections for:

* TV display: TV-out or S-video
* Analog video cameras: ViVo or video in/video out
* Digital cameras: FireWire or USB

Some cards also incorporate TV tuners. Next, we’ll look at how to choose a good graphics card.

Choosing a Good Graphics Card

A top-of-the-line graphics card is easy to spot. It has lots of memory and a fast processor. Often, it’s also more visually appealing than anything else that’s intended to go inside a computer’s case. Lots of high-performance video cards are illustrated or have decorative fans or heat sinks.

But a high-end card provides more power than most people really need. People who use their computers primarily for e-mail, word processing or Web surfing can find all the necessary graphics support on a motherboard with integrated graphics. A mid-range card is sufficient for most casual gamers. People who need the power of a high-end card include gaming enthusiasts and people who do lots of 3-D graphic work.

A good overall measurement of a card’s performance is its frame rate, measured in frames per second (FPS). The frame rate describes how many complete images the card can display per second. The human eye can process about 25 frames every second, but fast-action games require a frame rate of at least 60 FPS to provide smooth animation and scrolling. Components of the frame rate are:

* Triangles or vertices per second: 3-D images are made of triangles, or polygons. This measurement describes how quickly the GPU can calculate the whole polygon or the vertices that define it. In general, it describes how quickly the card builds a wire frame image.
* Pixel fill rate: This measurement describes how many pixels the GPU can process in a second, which translates to how quickly it can rasterize the image.

The graphics card’s hardware directly affects its speed. These are the hardware specifications that most affect the card’s speed and the units in which they are measured:

* GPU clock speed (MHz)
* Size of the memory bus (bits)
* Amount of available memory (MB)
* Memory clock rate (MHz)
* Memory bandwidth (GB/s)
* RAMDAC speed (MHz)

­ The computer’s CPU and motherboard also play a part, since a very fast graphics card can’t compensate for a motherboard’s inability to deliver data quickly. Similarly, the card’s connection to the motherboard and the speed at which it can get instructions from the CPU affect its performance.

source:
http://computer.howstuffworks.com/graphics-card.htm

NVIDIA SLI and ATI CrossFire have been around for quite a while now, but it’s only lately that the industry has seen a significant breakthrough and advancement in the technology.

If you don’t know what these 3D performance enhancing technologies do exactly, I’m sure you’ve at least heard of SLI and CrossFire before. In this article we will explain what SLI is and how it works, and you can read our other article on ATI CrossFire if you want to know about that too.

Back in 1998, the company 3DFX first introduced us to the SLI term with their Scan-Line Interleave technology used in their Voodoo2 range of graphics cards. NVIDIA then came along and bought 3DFX, and came up with a new idea of using the PCI-Express bus to increase 3D graphics performance. They named this new technology Scalable Link Interface (SLI).
How Does SLI Work?

NVIDIA SLI basically works like a dual core processor, it splits the load into two. With SLI you have two or more video cards connected together in a master/slave setup via what’s called an SLI bridge. When displaying 3D graphics on the screen, all the work is divided into smaller parts and sent to each of the GPUs for faster processing. When the slave GPU is done processing, it sends its output to the master GPU via the SLI bridge, and the master GPU combines everything to display the images to the monitor.

What Do I Need For SLI?

To use NVIDIA SLI in your gaming computer you must have a motherboard based on a NVIDIA chipset and you need at least two PCI-Express 16x slots. You also need two (or more) NVIDIA video cards that are SLI compatible.

You must keep in mind that the two or more video cards must have the same GPU (and preferably have the same memory and clock speed too), although they may be of different manufacturers.

If you’re buying a brand new card you can be sure that it is SLI capable, but if it’s a slightly older card you must be sure it can be used with SLI because not all of them can. So double check before buying a video card.

Different SLI Modes

NVIDIA SLI technology can be set to function in different modes.

* Split Frame Rendering (SFR) – This mode works by cutting each frame in half and sending it to each GPU for processing. Very simple.

* Alternate Frame Rendering (AFR) – Instead of breaking a frame into smaller pieces like SFR, AFR works by each GPU rendering a whole frame one at a time, one after the other.

* SLI Antialiasing(AA) – With just a single video card, you can enable antialiasing up to 4x. But with an SLI setup and multiple video cards, you can experience much more antialiasing such as 8x, 16x, 32x, and even 64x with a quad SLI system (4 video cards).

Quad NVIDIA SLI

Quad SLI is just what the name implies, four GPUs working together for amazing performance. It can be accomplished by either having 4 video cards slotted into 4 PCI-Express 16x slots, or 2 dual-GPU video cards slotted into 2 PCI-Express 16x slots.

As you can imagine, this will increase performance in your games. You will see the true power of quad SLI when you’re in high resolutions, and when you enable SLI Antialiasing mode.

source: http://www.build-gaming-computers.com/nvidia-sli.html

One of the most recent inventions in video card technology is that of the external video card. These external Graphics Processing Units (GPUs) plug directly into one of your computer’s USB ports and can potentially increase your 3D graphics performance.

External graphics cards are mainly targeted at those looking for high-end performance and those who want to run dual monitors.

But they are especially aimed at laptop users who want to upgrade their graphics performance. Most built-in laptop video cards don’t provide ample performance to run the latest games at good frame rates, and on top of that they tend to share the laptop’s physical memory which slows down performance. So if you’re looking to upgrade your gaming laptop’s graphics card then an external graphics card could be the answer.

Installing an external card is simple as most of them just plug directly into a free USB 2.0 port. Some external graphics cards install differently though, such as the Asus XGstation. This external card connects to what’s called an ExpressCard slot, which is built into most newer laptops. As well as providing extra performance for your laptop, plugging your external video card in this way give you the option of overclocking the card for even more speed and power. The Asus XGstation also comes with dual DVI connections to power multiple monitors.

The other great thing about external cards is that it can provide great high-performance 3D graphics without heating up your entire computer. The more powerful the card the more heat it will produce, but you don’t have to worry about this with external GPUs since they usually have their own external cooling system too.

The advantages of using an external GPU are obvious, but there are a couple of minor disadvantages that you might want to be aware of. The first being that you need to carry around the external card along with your laptop, and some of the more powerful units are quite bulky. The second being that most external graphics cards require their own separate power connection. In truth these drawbacks are very minor in relation to the benefits of external GPUs.

So that being said, if your laptop’s graphics performance is sluggish then you might want to consider buying an external video card to get your system running smoothly again. It’s definitely cheaper than buying a new laptop.

source: http://www.build-gaming-computers.com/external-video-card.html