DirectX is the multimedia system foundation for Windows operating systems. directx is the multimedia system foundation for windows operating systems. through directx, programs take full advantage of your system to give you the best multimedia experience possible. this latest version of directx offers updated graphics, faster frame rates, and support for massive multiplayer games. it also offers more immersive audio when running and displaying programs rich in multimedia elements, such as full-color graphics, video, 3d animation, and surround sound. if you had an earlier version of directx installed on your system, you will see little difference in available space on your hard drive following the installation. directx 8.1 will overwrite any earlier versions.