What is a video card?

Ever wonder what makes your computer monitor display stuff? It’s your video card. I realize that that’s not helpful to most people, so here’s an explanation.

What does it do?

Let’s say you click your mouse on a desktop icon to open an application. What’s really happening? You click, which sends an electrical signal from the mouse through a wire to either a USB or PS/2 port on your motherboard. The signal is then sent along the motherboard and to your CPU, which does some calculations and comes up with a response to your click. That response is sent through another electrical signal along the motherboard until it gets to your Graphics Processing Unit (GPU), which is on your video card. The GPU decides how to take that response and turn it into something visual to show you, and sends that change to your monitor, which refreshes, and voila!

I know that sounded like a mouthful, so I’ll lay it out simply. Your video card is responsible for taking the calculations that your computer does, and turning them into visuals on a monitor for you.

A little history

Video cards didn’t always exist. It used to be that the CPU (Central Processing Unit) would do all the calculations, but as computers got to be more sophisticated, manufacturers found they needed more power dedicated to video. This is how “GPU”s (Graphics Processing Unit) were invented. Today, there are two manufacturers that control the market, ATI and Nvidia. Most of the time it doesn’t matter which brand you pick, as long as you get a good deal. You can use the tomshardware.com video charts to find out what cards are top performers in your price range. There are also third party manufacturers that take the GPUs that ATI and Nvidia make, and factory overclock them. For example, an ATI Radeon X800 is a video card made by ATI. A third party company like XFX might take the GPU on that Radeon X800 card and overclock it a bit, put it a XFX GPU Cooler on it, and dub it the XFX Radeon X800. It’s always nice to buy these third party cards, because they are usually the same price, they are factory overclocked, and they look cooler.

Types of video cards

Before you buy a video card, you have to figure out what type your motherboard supports. Many motherboards come with integrated video, especially the lower end ones by OEM Manufacturers (Dell, eMachine, Gateway, etc). Almost all motherboards now come with expansion slots though, and this is where you’d put your graphics card. Some common types of expansion slots are: PCI, AGP, PCI-X and PCI-Express.

Once you figure out what type you need, you can choose one in your price range. Newegg.com is a great place to buy one.

Whats makes a particular video card better than another?

Video cards consist of a printed circuit board (the card) holding a Graphics Processing Unit (GPU), dedicated video memory, a GPU cooler/fan, and some other random electrical stuff like capacitors and resisters. The GPU is the most important part, but there are only a few specs overall to worry about.

Core Clock – How many cycles per second your GPU can process. The more the better.

Memory Size – How much dedicated memory your video card has on it, get at least 256mb these days, but 512 should be standard.

Memory Interface – Usually 128-bit or 256-bit. Higher is better.

Memory Type – Anything from DDR to GDDR5. Any GDDR type of memory should be fine but GDDR5 is the best at the moment.

Memory Clock – How many cycles per second your memory can handle.

As long as you use tomshardware’s guides you won’t really need to look at any of these things, except memory size which is pretty important. You’ll also notice that the GPU clock and memory clock will be higher on 3rd party cards than on the factory ATI and GeForce ones. Also, the cooling might be more innovative.

SLI and Crossfire

Both Nvidia and ATI have technologies that allow you to have put multiple video cards on one motherboard, which gives you added performance. Logically, you would think that you would get 2x the performance because you have twice as many cards, but in reality it ends up being 1.5x the performance.  Therefore most of the time it’s not worth it to shell out for two cards, just get a top of the line card instead.

Double GPU Cards

Some video cards come with two GPU’s on one card. This is more of a prestige thing than performance, it’s just so you can say you have it, kind of like having a nitrogen powered  CPU cooler. I’d rather have Crossfire or SLI than a double GPU card, just because you get twice as much memory and therefore better performance.

Last but not least

You can buy the most expensive video card, but if you have a monitor that uses VGA instead of HDMI or DVI, you wasted your money. Using the most expensive video card in a low resolution is like using a Ferrari in a 25 mile per hour zone. Also, make sure you get the most up to date drivers, get them from your manufacturer’s website (don’t use the CD that came with the card). You can also try the third party drivers and forceware on guru3d.com. They work great.

I hope you learned a little bit about video cards, if you have any further questions feel free to post them in the comment boxes below…

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