NVIDIA has updated their alternate graphics drivers for OS X Mountain Lion 10.8.5. These are separate from the drivers Apple ships as standard, and should be considered experimental. If you've installed the drivers before you can update from System Preferences. NVIDIA Web Driver 313.01.03f01 http://www.nvidia.com/object/macosx-313.01.03f01-driver.html How to Install the Web Drivers: In order to flag the alternate drivers on a CustoMac, you must install the package and also add the flag manually to the chameleon.org.Boot.plist. For Chimera bootloader: 1. Open Finder 2. Navigate to /Extra/org.chameleon.Boot.plist 3. Open in TextEdit 4. Add nvda_drv=1 to Kernel Flags as shown: Example Usage: Code (Text): <key>Kernel Flags</key> <string>darkwake=0 nvda_drv=1</string> 5. Save and reboot You should be on the new NVIDIA drivers. Related: NVIDIA Updates Web Drivers for 10.8.4 (313.01.02f01) NVIDIA Releases Mountain Lion 10.8.3 Graphics Drivers Please note that these drivers should be considered experimental. If you aren't having any issues, do not install- the native OS X drivers work great for most people.