I'm convinced that constantly upgrading nVidia drivers for older video cards simply doesn't matter. I have been using a GeForce2 GTS for 6+ years. They stopped making drivers for it in the 70-series. However, the games I care about preform the same with drivers from 70, 60, and 50-series. Heck, those games performed better under Windows 98 using 20-series drivers.

Of course, your newer cards playing newer games may be more effected. The above is just an interesting data point.