There are three eVGA versions of the 7900GT.
The 7900GT CO uses the same "board" as the superclocked edition, and so sometimes when some people have purchased the superclocked edition, it has come at the speeds of the CO edition. This is no big issue, because eVGA overclocks the superclocked edition the same way a customer would, as long as you are capable of overclocking a video card of course.
But don't fret, this doesn't even effect your card model and shouldn't unless eVGA is having organization issues with this card model too ^_^. If it infact is incorrect, eVGA is very good about replacing your product.
The driver is simply some software that you can download off of Nvidia's site that allows your video card to run smoothly with the latest software for best performance and such. Nothing complicated
I believe you can check the speed and settings of your video card in the BIOS, if not hopefully someone else can help you with that by posting a piece of software that can.
For most computer setups, holding the delete key during startup will take you to the BIOS.
Hope this helps you.