OS X GeForce GT 640M drivers for Mac OS X

[afcio]

Hey. I got a late 2012 new iMac with GeForce GT 640M. I've been wanting to play The Witcher 2, which I just bought off of a deal on GoG. However, the performance is piss poor on low settings. That made me look around for graphics drivers for my computer. The game itself, as most games actually, automatically set high settings, so the computer isn't bad. But I can't seem to find any legit drivers for the 600M series of GeForce which address Mac OS X. Any ideas?

 

[monokitty]

The drivers are built into OS X; it's not like Windows where you can download new or different graphic card drivers. Driver updates, if applicable, are built into incremental OS X updates (i.e; 10.8.4).

 

[cluthz]

The witcher 2 in osx runs really bad on my GTX660 too, but in win7 it runs like a champ.
The witcher 2 port is just very poor, with less than 50% of the performance in windows.