What I would do is go into device manager by right clicking my computer and going down to properties and clicking the device manager tab. Expand the display adapters thingy by clicking it, highlight your old card, and click remove. Then shut down, dont restart, your computer, and install the new card. Then install the new drivers when your comp boots up.
Yeah... bout' the only thing you wouldn't want to overclock, would be your clock...
Unless you just want to be early all the time..