Ripley, what kind of monitor do you have? How is it set up? What type of connector do you use on the cable? What settings have you got on the card itself?
I have never had problems with poor 2D quality with Nvidia, ever. I have worked in computer labs and seen non-Nvidia cards go all fuzzy on the screen, but we're talking monitors that have to last until they burn out, budget cards, and cheap setups.
I wonder if the card is fine but something else is causing the problem.