I should have been more clear. I am planning on buying a new computer, probably HP (i-7 processor) and am not sure about their options for video cards. I wanted to figure out what makes sense to include and whether it makes sense to buy two video cards from HP, or if it makes sense to add an extra card on my own.
I guess the advantage of two cards is if I want to add a fourth monitor I could do it without purchasing another card.
I am not a gamer, just use it for day trading with a lot of charts.