Dual Graphics Cards - Need Tech Asst.

[McClain]

I have an NVIDIA GeForce 4MX420. The one recent card that Splinter Cell Pandora Tomorrow doesn't support. Fucking hardons. Anyway, I understand that you can hook up two graphics cards. I want to buy another one so I can play the game. Prolly a 64MB ATI or something from the GeForce 3/4 family.
How do dual graphic card setups work? I'm not doing this so that I can have two monitors but more so I can play this damn game.
Is there a master/slave card setup? Is it a pain in the ass?