Microsoft DirectX* is a set of APIs (application programming interface) for games and multimedia applications. Some DirectX components require support from the graphics driver in order to function properly and provide the best gaming performance.
Microsoft DirectX Download Information
OpenGL* is an application programming interface (API) for 3-D graphics used by many games. OpenGL enables hardware acceleration of 3-D graphics. Support is required from the graphics drivers for optimum performance.
OpenGL Information from OpenGL.org
OpenGL* Settings Guide
OpenCL* (Open Computing Language) is a cross-architecture, cross-operating system, open standard, heterogeneous parallel programming environment. Open CL allows the applications to target processors, graphics processing units (GPUs), embedded processors, digital signal processors (DSPs), and other available compute resources in a system.
Intel® SDK for OpenCL* applications
Khronos OpenCL* Web site