Today at college my friend said that installing 2 graphic cards instead of 1 where both are of the same memory size improve gaming experience. How far is this true? Will I get any advantage by adding another 1 GB graphic card. Also what are the different advantages of adding a graphic card, according to me a graphic card is needed only for gaming purpose?
Adding a second graphics card is similar to having a dual-core processor in that both graphics cards (more specifically, the GPUs) will share the processing load. You will probably only notice the improvement during gaming, unless you're doing something else that puts a large demand on your graphics card.
The graphics card is not only used for gaming. It handles graphics processing all the time, but merely browsing the Internet or typing up a document doesn't require much from the graphics card. Since the latest versions of Windows are rendering the desktop using DirectX, a greater demand is starting to be placed on the graphics card.
Both the motherboard and the cards have to have support for this built in. Look for either "SLI" (nVidia cards) or "Crossfire" (ATi/AMD cards).
Graphic cards can help in a few areas outside of gaming. Several tasks can sometimes support off-loading some work to the graphics card:
But you're probably not doing the latter two and if you have a computer capable or running recent games you probably don't need it for the first item. If you really want a fast computer, spend the money on a quality SSD.