A big thanks to eduello and DSzymborski for helping me to know the facts.
Update 1: Hey eduello, I have decided not to purchase a graphics card. Instead, I'm going to buy a new processor. The person who is selling that card was very rude while he was speaking with me through telephone. Also, he is not giving out a proper assurance of his card, making me to think the card has a defect.
Update 2: Waiting for RobCrezz's comments to make sure I'm going in a right direction.