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Day 13 – What is a Graphic card? Why we need a Graphic card? How it works?

Most of budget and mid-range PC users could not have got any chance to see a Graphic card. This is because they might not have needed a discrete Graphic card.

Earlier it was a thought that Graphic cards are only meant for gaming. But nowadays Graphic cards are needed in each and every operation that we do in computer.

We have got used to transparency looks, Aero desktop, HD resolution videos etc.

What does this actually mean?

These processes actually use a graphics processor, but these are taken care by your processor as well as onboard graphics.

Then why do you need a graphics card?

Before as usual, let me ask you What is a Graphic card? or Show me the Graphic card, if you have one.

Graphic card is usually looks like a mini motherboard, with inbuilt graphics processor over which one or two fans will be rotating. If you have graphic card then that is where you would have connected your monitor signal cable, i.e. VGA adapter or DVI connector. It is located well below the processor and is fixed upright or perpendicular to the motherboard.

Why we need a graphics card?

I have explained the need of graphics card several times before, in APU section and onboard video section, so I do not want to bore you again. To summarise, Graphics cards are needed for

1.     Full HD video playback

2.     3D gaming

3.     Responsive PC while using Aero desktop feature in Windows 7 or 8

How it works?

If we go deep into the working of graphics card, then it will be somewhat out of the scope of our course, so let me touch the overview of working of graphic card. Compared to our processors which have 2 or 4 cores generally, graphics cards have more than 100 cores. But that doesn’t mean graphics cards are 50 times more powerful than processors.

In processors section, I have compared processors to horses and rhinoceros, comparatively Graphic cards’ cores can be compared to cats.

Now you can understand the difference between both. A horse cannot do the things what 100 cats can do; also 100 cats cannot do what a horse can do. So we need both processor and Graphic card.

But how much power we need in each of them is the question here?

Graphics cards basically works on each pixels or group of pixels, that’s why a higher resolution monitor needs a highly powerful Graphic card. Similarly, to play a video with higher resolution, high power Graphic card is needed; the same is the case of Games too.

Graphics cards get data from CPU, through motherboard and process the data into digital image, which is then converted to analog image. This analog image is displayed in the monitor. Usually a Graphic card contains 2 output display port, so we can connect at least 2 monitors to a Graphic card.

What factors determine the speed of the Graphic card?

Performance of Graphic card is usually determined by ‘FPS’ or frames per second. It means how many frames the card can generate in a second. Sometimes the performance can also be measured by ‘fill rate’, but for now, those things are not needed, because we can learn those things in Graphic card buying guides.

Some other factors with which we can identify the performance of Graphic cards without even testing them with some software are mentioned below. These factors can be identified from the specification sheet of the Graphic card. They are:-

1.     GPU clock speed (MHz)

2.     Size of the memory bus (bits)

3.     Amount of available memory (MB)

4.     Memory clock rate (MHz)

5.     Memory bandwidth (GB/s)

6.     RAMDAC speed (MHz)

Don’t get confused with these terms now, if you don’t understand what they are and what they actually mean. We will see to them in detail during our Graphic card buying guide section.