First let me welcome you to the forums . And second , I think that is how it will be with 2 cards . I could be wrong . If you want it to span between the two that the fish swim from one screen to the other like I do , I think you need a card that has the 2 video heads . Like I have a GeForce FX 5900XT and it looks great . I had a GeForce 4 ti 4200 and it too looked great .
Someone here will let you know if I'm right or not .
Again , Welcome .