In order to use the alternate drivers on a CustoMac, you must first install the driver package. NVIDIA Alternate Graphics Drivers for OS X 10.11.2 (15C50)
If you've installed the drivers before, you may get a notification to update to the new drivers from the built in System Preferences pane. NVIDIA CUDA Getting Started Guide for Mac OS X DU-05348-001v6.5 2 Table 1 Mac Operating System Support in CUDA 6.5 Operating System Native x8664 GCC Clang Mac OS X 10.9.x YES 5.0, 4.2 Mac OS X 10.8.x YES 4.2.1 5. Release Notes Archive: This driver update is for Mac Pro 5,1 (2010), Mac Pro 4,1 (2009) and Mac Pro 3,1 (2008) users only. Includes NVIDIA Driver Manager preference pane. There are no current Macs with these cards, so support is absent natively in OS X. Graphics driver updated for Mac OS X Mavericks 10.9.4 (13E28) Contains performance improvements and bug fixes for a wide range of applications. NOTE: These drivers are currently the only method to get full acceleration for NVIDIA GeForce GTX 750, 750 Ti, 950, 960, 970, 980, 980 Ti, and TITAN X 'Maxwell' graphics cards. These drivers have been known to solve OpenCL issues with certain applications, as well as providing better native GPU power management for certain devices. You should configure Clover or Chameleon to make nVidia. /rebates/&252fhackintosh-nvidia-drivers-mavericks. Having to a nightmare for Vanilla Installation method. Apple has also discontinued support for NVIDIA Web Drivers from the first release of macOS Mojave, to current. These are separate from the drivers Apple ships as standard, and should be considered experimental. Nvidia MacOS Driver Installer automatically tries to install the correct version of web-driver aka Nvidia Alternative Driver for your macOS. Graphics driver updated for Mac OS X Mavericks 10.9.4 13E28 Contains performance improvements and bug fixes for a wide range of applications.
NVIDIA has released alternate graphics drivers for OS X El Capitan 10.11.2. Building a CustoMac Hackintosh: Buyer's Guide