The chances of a new set of drivers reducing your performance is virtually non-existant, especially coming from Nvidia. IF it reduces a card's performance, WHY release them? Drivers aren't things you want to swap out repeatedly. They're too important to mess around with a lot. 95% of the time, a new driver update will not NOTICABLY increase or decrease your card's performance. If all you're looking for is the best possible benchmark scores, then stick with the most current driver set.