They shouldn't. If you visit the nVidia website theres different drivers for the different familys. for a reason.
Nvidia use what they call a "unified driver" or one size fits all approach, the current driver is for all cards from the 6 series to the 4xx series. I have found that whilst you can get away with installing a new driver over an old one it's best to remove the driver and reinstall it if you change cards.