Video cards (also known as 'graphics' cards or graphics adapters) are the part of the computer that convert the digital data to analog (and sometimes digital) video. As was mentioned earlier, some motherboards have integrated video processors but those video processors are typically only good for basic computer operation and for playing simple games. If you want to play high-end computer games (World of Warcraft, Call of Duty, Grand Theft Auto, Splinter Cell, Half Life 2, Crysis...) or if you want to reduce the load on your processor, you will need a better video card. The following image is a relatively low end video card but it's significantly better than the typical integrated video processor. THIS one is a mid-range graphics card (in March of 2010).

Video Output Connectors:
In the image above, you should notice a couple of things. There are 3 connectors on the end panel. The left-most connector is a D-sub/VGA connector and is used to drive a standard computer monitor. Basic video cards have only the blue connector. Recently, more video cards have been offering more options for graphics output. The center connector is an HDMI connector. On the right, is a DVI connector. Either the HDMI or the DVI outputs can be used to drive the digital input of a monitor or HDTV. The right-most connector can also be used with a standard computer monitor through an adapter.

You should also note that this is a 'single slot' card. This means that it only takes up one expansion slot. Larger cards take up two slots and can be more difficult to fit into some cases.

In some instances, a user will need two monitor outputs but the monitors will only have D-sub connectors. The DVI connectors also contain analog (VGA) output signals. To get the VGA signal, you use an adapter like the one shown below.

This is what the HDMI connector that plugs into the video card looks like.

The following is a DVI to HDMI adapter. If you look at the at the area around the flat terminal, you can see that it doesn't have any pins above or below it. Those are for the analog video and are not needed for the HDMI signal.

Note:
Some video cards have composite video and S-video outputs. The composite and S-video output signals are fine for watching videos or movies. They are, however, not suitable if you want to use a large TV as a second computer monitor unless the computer has VGA or digital video inputs. The resolution of a TV is far below that of a computer monitor. The display of the computer's desktop on the TV will be very difficult to read. If you want to use your computer with a television monitor, you'll need one with DVI or HDMI inputs.

Some video cards (like the HD 5570 or the HD 4870 shown on this page) can take the S/PDIF signal from the PCI-E buss bit some require that you connect the S/PDIF signal with a 2-conductor cable. The card below is a GeForce 9600 GT. It shows what the connector on the card and the cable look like. The other end of the cable connects to a 2-pin header on the motherboard.

Power Supply Requirements:
Graphics cards have to do a lot of work and that work requires power. For low to mid-range cards, the power will typically come from the connector on the motherboard. For high-end cards, you will typically see a dedicated power connector like the one below. The power requirements are important to consider because ultra high-end cards can require that you use a power supply rated for much higher current than you'd normally need for an average computer. If a video card has power connectors on it, it will almost certainly need to have auxiliary power. Generally, the power connectors are dedicated PCI-E connectors but there are some that use a connector like those for floppy drives.

Cooling:
On all of the video cards on the site, there are heatsinks on the video graphics processor ICs. The heatsink is there to cool the GPU. The GPU (graphics processing unit) is similar to the microprocessor on the motherboard but is specifically designed to process video signals. Like the CPU on the motherboard, the GPU produces heat. The more intense the graphics, the more heat is produced. On low-end cards a simple heatsink will keep the GPU cool. On more powerful video cards, you will see larger heatsinks and fans to keep them cool.

You can see that this card has a fan. Most newer, high performance cards have fans. Even though this is a relatively low end card, it uses a fan to help keep the operating temperatures down. During normal computer use (surfing the web, working on documents...), the video processor isn't run very hard and wouldn't need a fan. For those who play video games with 3D graphics, the demand is much higher and the fan is required to prevent the card's GPU (Graphics Processor Unit) from overheating. For those who want a silent computer, there are silent cards that have HUGE heatsinks that can dissipate significant heat. These generally rely on convection or air flow through the case to help dissipate heat.

The card above (Nvidia GeForce 8500GT) is a relatively low powered card and is therefore easy to cool. The small heatsink is in direct contact with the GPU and is small enough to be cooled directly. For cards that produce more heat, you need a different type of cooler. It's important that a graphics card not be too thick. If it's too thick, it will cover too many slots on the motherboard. Since it's not possible for a large, thin heatsink to conduct heat efficiently far from the source of heat, a solid heatsink (like the one above) isn't practical for higher powered cards. The card below (Asus HD 4870) is a midrange card that produces significant heat when it's working hard. To cool it, heatpipes are used. Heatpipes have a liquid in them that boils off when heat is applied to it (by the GPU in this case) and as it boils off, the heatpipes absorb heat. The internal construction of the heatpipe causes the heated coolant to move away from the GPU. The heatpipes are bonded to fins. The fins pull heat from the heatpipe and provide significant surface area to dissipate the heat. To help increase the cooling, a fan is used to force air over the fins. All of this works together to keep the GPU operating at a safe temperature.

Earlier, it was mentioned that there are single-slot and double-slot cards. The one at the top of the page (a Sapphire HD 5570) and the 8500GT are examples of single slot cards. The one immediately above is a double-slot card. You can see that it has a rear panel that fills two of the expansion slots.

A note on safety...
Many of the newer fans have their blades designed to be as quiet and efficient as possible. For some, the blade design results in a sharp point on the leading edge of the blade. The fans with shrouds aren't a problem but the ones that have no shrouds, like the one below, can quickly draw blood. When working in a computer that's powered up, you need to be careful around shroudless fans.

The following image shows a graphics card without the heatsink. The large square IC in the center of the board is the GPU. The 8 black ICs are the memory modules. Many times, there are pieces of thermal gap pad between the memory modules and the heatsink. These help transfer heat from the memory ICs to the heatsink.

Chipsets:
Chipsets are the graphics engines used on the various video cards. There are many different video card manufacturers but virtually all of them use chipsets manufactured by either AMD/ATI or Nvidia. The chipset determines the capability of the graphics cards. In many instances, the video card manufacturers simply take a 'reference design' that's provided by the chipset manufacturer and lay the circuit out on the board. The video card manufacturer only has to decide what features to offer from the chipset, the types of interfaces (video output plugs, etc...), the cooling solution and the way the card will look. Sometimes, they'll write their own drivers and for some of the high-end cards, they may have to design a power supply for the chipset but most of the hard work was done by the chipset manufacturer.

Memory Sharing:
When you have a graphics processor integrated into a motherboard, you have to share both CPU power and memory. With a dedicated video card, there is no need to do either. Most integrated video cards share at least 32MB of system memory. More commonly they share 64MB of system memory. High end 'gaming' cards often have 1000 MB (1GB) of memory. In some of the better gaming cards, the memory is optimized for video (GDDR5 is commonly used on high-performance video cards).

Memory:
This tells you what type of memory (DDR, GDDR2, GDDR3, GDDR5...) and the quantity of on-board memory. DDR is Double Data Rate. GDDR is Graphics Double Data Rate. It means that it's optimized for graphics.

Effective Memory Speed:
This tells you the rated memory speed. It can sometimes be confusing due to double data rate memory. DDR memory is rated at twice the clock frequency.

Chipset/Core Speed:
This is the clock frequency of the GPU.

Ports:
This tells you what type of signals it can deliver. The common outputs are S-video, composite video, standard VGA output and DVI out. Some also have input ports.

Maximum Resolution:
This tells you the absolute maximum resolution. The specs usually include refresh rate, color depth (in bits) and the screen resolution. A common spec for resolution may be 2048x1536@32bit color at 85Hz. This tells you that it can produce a display of more than 3 million (2048x1536) pixels at a rate of 85 frames per second. 60 frames per second is generally enough for most people but a few find that the image seems to flicker a bit so they may opt for a slightly higher refresh rate 75Hz or 85Hz).

Video Card Connectors:
The following image shows the connectors for the three most common video graphics card motherboard connectors. As you can see they're all very different. When buying a card, you need to know what sort of slot the motherboard has so that you can get the right card. Since the PCI slots are on most motherboards, it's sort of a universal video card but it's not the best choice if you want a high performance graphics card (which is required for virtually all 3D computer games).

As you can see above (you can right-click to zoom in), the AGP connectors are very closely spaced. This caused a lot of problems when the cards weren't fully seated in their sockets. Starting with the AGP motherboards and continuing with the PCI-E boards, there are latches to ensure that the backs of the cards remain fully seated. In the photo below, you can see the white sliding latch at the right-end of the blue PCI-E connector. It's important that you slide the latch into place (locking the card in the socket) when you install a PCI-E card.

Although this doesn't apply to graphics cards, PCI-Express has been mentioned. The PCI-E connector above is a 16x interface. For applications where the data transfer rate doesn't need to be as fast as it does for graphics cards, 1x, 2x, 4x and 8x interfaces are used. The following is a 1x card. It's used for a parallel printer interface. I know many of you are asking why I'd still be using such an old printer. Well, it's because it's one of the best printers I've ever owned. It's an old HP Laserjet 4+. It's not disposable like newer printers. With minor maintenance (spare parts are readily available), the printer still works like new. The 1x, 2x... tells you how many data 'lanes' the interface has. The more lanes, the faster the maximum data transfer.

As a Side Note...
'Drivers' haven't been covered yet but I thought this should be mentioned here. Drivers are software that tells two pieces of equipment how to communicate. All drivers are not created equal. Generally, the latest drivers are the best. The drivers delivered with the hardware are rarely the latest version. For example, the card above which was purchased in March of 2010, had drivers produced in 2007. Testing (benchmarking) showed dismal performance from this card. I had two other computers with integrated graphics adapters that outperformed this card. After updating the drivers from the manufacturer's web site, this card easily outperformed the integrated graphics adapters (as it should have).

On many of the graphics cards with heatsinks, the heatsinks are held in place by (weak) spring clips. These can be seen in the photo below.

If you bump the heatsink so that it is separated from the GPU, the GPU could fail. If the heatsink extends beyond the edge of the board, this is very easy to do and you may not even know that you did it. There is a layer of thermally conductive material (like you will see on the upcoming More on CPUs page). When the heatsink and the GPU are separated, the thermally conductive material isn't likely to remain perfectly distributed and is VERY unlikely to be able to efficiently transfer heat from the GPU to the heatsink. If you think you may have separated the sink from the GPU, download a program like PC Wizard that will allow you to monitor the temperature of the GPU. If it goes above ~60C at idle, you may have a problem. It's true that some high end GPUs will operate that hot if the fan is set low to minimize noise but most low to midrange graphics cards won't run that hot at idle.

To help increase the performance of a computer's graphics processing system, sometimes multiple video cards will be used. Nvidia calls it SLI. AMD/ATI calls it CrossfireX. Sometimes as many as four cards are used to produce output to a single monitor. Below, you can see that two relatively inexpensive cards have been installed. These would not have been a good choice because you could likely get better performance from a single (better) card for less money. I had these from other systems I built so I installed them just to see what they would do. When installing multiple cards, you have to enable the use of them in the software provided by their manufacturer. In some instances, you will have to install a jumper (supplied with a motherboard, the cards or separately by the manufacturer -- second image below) between the cards. For low powered cards like these, the connection between the cards is made through the motherboard.

This shows a Crossfire jumper installed on two video cards. The extra connectors are to connect additional cards to the existing cards.

Previously, it was mentioned that the heatsink is often held onto the GPU with weak spring tension and that you should check the operating temperature of the GPU under load. If you have multiple cards running in crossfire mode or a similar configuration, compare the temperature of the two cards. They should operate at approximately the same temperature when under load (gaming, benchmarking...). If one runs significantly hotter, it may have a problem with the thermal transfer from the GPU to the heatsink. The PC Wizard won't always show multiple cards but the manufacturer of the video cards that you're using should offer some application to show the operation of the cards. For ATI, there is a program named Afterburner. It shows the temperature of the various video cards, the fan speed, the load on each card. If both cards are driven to 100% and one is operating10-15° hotter, you need to determine what the problem is before you destroy the video card.

In the following photo, you can see that there are 3 blue PCI-E slots. Physically, the slots are identical but they don't all have the same electrical connections. The long PCI-E slots can have up to 16 data lines. In this board, only the left-most two have 16 data lines. The one at the far right has only 4 data lines. This is common. On most moderately priced motherboards, there is only one 16x PCI-E slot and one 4x PCI-E slot. The ones closest to the CPU are going to be the 16x slots. When installing a video card, you want to install it in the slot that has the ability to transfer data at the highest data rate (the 16x slot). If you install it in one of the 8x or 4x slots, it will work but will not perform as well as it could in the 16x slot.

VIVO:
VIVO stands for Video In Video Out. Graphics cards with VIVO can produce video to play on a standard TV and can accept a video signal to act as a video recorder (when the proper software is installed). VIVO cards often use a mini-DIN connector similar to that shown on the rear of the card at the top of the page. The audio input and output signals are passed through the sound card of the computer. VIVO cards typically have no tuner. They can generally only process composite video or s-video signals. If you want a card with a tuner, you need a video capture card or an all-in-one card.

In the following image, you can see the VIVO interconnect cable. It has two video input cables and two video output cables. Each input and output has two different connectors. The smaller connector is for 'composite' video. The larger connector is for S-video.

If you're not using an HDMI output from your video card, you may have to use the sound card inputs/outputs on your sound card to get the audio portion of any video you're passing through the computer. Many times, you have to use RCA type connectors. Since the computer has mini-phone (1/8" phone) connectors, you'll need an adapter cable.

Video Converters:
If you want to show the computer's display on an older television that doesn't have any digital inputs, you can use something like the converter below. It takes the computer's VGA output and converts it to composite video and S-video. There are video cards that can produce composite video and S-video but they're getting harder to find and they rarely offer high performance. This one has a pass-through function for the VGA signal but it doesn't work well. After the video signal passes through it (to the computer monitor), it's not nearly as sharp as when driven directly from the computer. Fortunately, the graphics cards had two outputs so one could be used to drive this and one could be used to drive the computer monitor. When buying something like this, you have to be aware that they all can't accept the high resolutions that you may use on your monitor and to use the converter, you may have to reduce the resolution from the video card which will reduce the resolution going to the monitor. This one has a maximum resolution of 1152x864. When using this, the computer's output has to be set to 1152x864 or lower for the converter to produce any output. If you use your monitor at 1280x1024, buy one that will work at that resolution. If you use a wide-screen monitor with full HD resolution, expect the converter to be expensive. This one was only about $60. Those that accept higher resolutions are much more expensive.

The remote is necessary because the output of the converter won't likely fit/fill the TV screen and isn't likely to be centered.

You May Be Interested in My Other Sites All Sorts of Stuff: This site was started for pages/information that didn't fit well on my other sites. It includes topics from backing up computer files to small engine repair to 3D graphics software to basic information on diabetes. Basic Macro Photography: This site introduces you to macro photography. Macro photography is nothing more than the photography of small objects. It can take quite a while to understand the limitations associated with this type of photography. Without help, people will struggle to get good images. Understanding what's possible and what's not possible makes the task much easier. If you need to photograph relatively small objects (6" in height/width down to a few thousandths of an inch), this site will help. Air Rifle Links and Demos: If you're interested in air rifles, this site will introduce you to the types of rifles available and many of the things you'll need to know to shoot accurately. It also touches on field target competition. There are links to some of the better sites and forums as well as a collection of interactive demos. Basic Car Audio Electronics: This site is for those who want to install or update their car stereo. It begins with the most basic electronics theory, progresses into basic transistor theory as well as covering virtually everything associated with car audio.