Altering Some Resistors Changes One NVidia Card to Another One (and this explains the Linux driver situation)
This article explains how to hack an NVidia card to make it act like a better model. The hack is basically to modify the identification of the card, so the driver unlocks a feature to enable multiple screens. Now, allofasudden, I understand why the NVidia drivers for Linux are closed source: if they offered open source drivers, they would invariably enable all the features to all the cards.
The point of the closed source drivers isn't to provide the best performance (though they usually do that because they are probably better written than the open source ones) but to allow NVidia to disable features to the cheaper card, despite the fact the cheaper card can perform exactly like the more expensive card.