The Most Comprehensive AMD Radeon Linux Graphics Comparison

Radeon X1800XL: This is an ATI-branded Radeon X1800XL (it was sent over by ATI Toronto in preparation for the R500 Linux support launch) with the R520 core running at 500MHz and 256MB of GDDR3 video memory at 1000MHz. The Radeon X1800XL is in the same Linux support boat as the other X1000 series parts.

While the R500 open-source Linux support is quite good and many Linux desktop users use it without complaints, there are two hardware features that have never been supported by the open-source Linux driver: CrossFire and UVD.

The Radeon X1000 series introduced ATI CrossFire as a means of multi-GPU rendering support similar to NVIDIA SLI. The R500 GPUs shipped with first-generation CrossFire that relied upon using a DVI dongle Y-cable, etc. It is unlikely we will see first-generation CrossFire ever supported by the open-source Linux stack. AMD did not even support first-generation CrossFire by its proprietary Linux driver. The open-source Linux driver stack and X.Org lack the necessary infrastructure to support multi-GPU rendering in a manner like SLI and CrossFire at this time. It is also a matter of development manpower with most of the Linux graphics contributors being preoccupied with other features and action items of higher priority. If CrossFire support ever comes to open-source drivers, by the time it does, users would be better off buying a $20 modern GPU of the time then running vintage R500 GPUs.

Open-source support for UVD, the AMD Unified Video Decoder engine, is a more sought after feature than CrossFire. While many users want this support so that they can move their video playback process to the GPU rather than taxing the CPU, chances are we will not see this open-source support either. While Advanced Micro Devices tries to be open-source friendly, they refuse to document or provide sample code for the UVD engine. The UVD area of the graphics processor is off-limits to official AMD open-source support over fears that exposing it could lead to compromising its Digital Rights Management mechanisms on other operating systems. Over fear of legal hot water, there is no open UVD support. Even for modern (Radeon HD 6000 series) graphics cards with the newer UVD engine, this is still the case of fear about a compromised Digital Rights Management system. With a future generation (likely the Radeon HD 8000 series) there may be a more modularized Unified Video Decoder implementation that would allow taking advantage of the video engine without potentially breaking the DRM system, but that remains to be seen and won't do any good for users of older graphics cards.

While the UVD engine can't be tapped by open-source drivers, there is some open-source support for all modern Radeon graphics processors (using R300 / R600 Gallium3D) with video decoding by using Gallium3D with its support for accelerating various formats using XvMC / VA-API / VDPAU. This is more of a focus now for the R600 Gallium3D driver, but there is some support in R300g too. The video support in Gallium3D driver is not tapping UVD but rather is offloading portions of the video playback process to the GPU by using the 3D engine with custom shaders. This Gallium3D video decoding support is still a work-in-progress, but it has been moving quickly in recent months. In 2012 the support will hopefully be in good standing and begin to appear in desktop Linux distributions by default.