Updating graphics card mac
Besides the drivers that Apple bundles with OS X updates, Nvidia also provides their own driver updates for their Ge Force cards — yes, even the "mobile" cards that Apple puts in Macs.As far as I know, this is not true of AMD and Intel.Which one you get to use in any particular game etc is up to the writers of that game.
An integrated graphics processor is a small graphics chip that is actually part of the Mac's main processor (CPU) - rather than having a 'dedicated' graphics card (or GPU - 'graphics processing unit'), which is a completely separate graphics card that works alongside the main CPU in order to give graphics performance a much bigger boost.
The latter seems more plausible to me, but either is just speculation.
The end result, though, is that there are rarely issues with Apple graphics drivers & regular software or games; again speculation, but for games I imagine they write to a pre-defined rule-set, rather than try to constantly be pushing the boundaries.
If you do install the Nvidia driver, though, you'll always have the option to switch back to the default driver or even uninstall the Nvidia driver via System Preferences.
You'll also be able to update the driver from there.