With hardware 3D acceleration, three-dimensional rendering uses the graphics processor on your video card instead of taking up valuable CPU resources drawing 3D images. It's also referred to as "hardware acceleration" instead of "software acceleration" because without this 3D acceleration your CPU is forced to draw everything itself using the Mesa software rendering libraries, which takes up quite a bit of processing power. While Xorg typically supports 2D hardware acceleration, it often lacks hardware 3D acceleration. Three-dimensional hardware acceleration is valuable in situations requiring rendering of 3D objects such as games, 3D CAD and modeling.

In many cases, both binary and open-source drivers exist. Open-source drivers are preferable since we're using Linux and open source is one of its underlying principles. Sometimes, binary drivers are the only option, like with nVidia's cards. Binary drivers include x11-drivers/nvidia-drivers and x11-drivers/nvidia-legacy-drivers for nVidia cards and media-video/ati-drivers for ATI cards. Other open-source drivers include media-video/kyro-kernel for KyroII cards and media-video/ati-gatos for ATI cards, which aim to support ATI's video capabilities more fully.

The Direct Rendering Infrastructure, also known as the DRI, is a framework for allowing direct access to graphics hardware in a safe and efficient manner. It includes changes to the X server, to several client libraries and to the kernel. The first major use for the DRI is to create fast OpenGL implementations.

X11-DRM is an enhancement to Xorg that adds 3D acceleration for cards by adding the kernel module necessary for direct rendering.

This guide is for people who can't get direct rendering working with just Xorg. X11-DRM works for 3dfx, gamma, i8x0, matrox, rage128, radeon, mach64 and sis300 series drivers. VIA card owners should not use x11-drm, but should instead use the DRI provided in recent kernels (>2.6.13). See the DRI homepage for more info and documentation.

With suggestions, questions, etc., e-mail Donnie Berkholz.