Radeon (/reɪdˌɒn/) is a brand of graphics processing units (GPU) produced by Advanced Micro Devices (AMD), first launched in 2000 by ATI Technologies which was acquired by AMD in 2006. Radeon is the successor to the Rage line. There are four different groups, which can be differentiated by the DirectX generation they support. More specific distinctions can also be followed, such as the HyperZ version, the number of pixel pipelines, and of course, the memory and processor clock speeds. The brand was previously known as "ATI Radeon" until August 2010, when it was renamed to create a more unified brand image. Products up to and including the HD 5000 series are branded as ATI Radeon, while the HD 6000 series and beyond use the new AMD Radeon branding.

ATI's Windows Radeon driver package is called CATALYST. The CATALYST software was instituted after the release of the Radeon 8500, as a marketing effort to match nVidia's universal Detonator driver packages. This new driver development paradigm at ATI promised monthly driver updates which included performance enhancements, bug fixes, and new features. As of 2006, the CATALYST driver package typically included ATI's CATALYST Control Center; an interface for manipulating many of the hardware's functions within Windows XP, such as 3D settings, monitor controls, video options, among other things. It also offered a small 3D preview, allowing the user to see how changes to the graphics settings affected the quality of the rendered image. The old control panel interface (within Windows' Display Properties) was previously a fall-back option, but that has been discontinued as of CATALYST 5.13. The CATALYST package can be downloaded in pieces as well, for non-broadband users. For example, the display driver can be downloaded alone, separated from the CATALYST Control Center and WDM VIVO drivers. The day that Microsoft Vista launched, ATI provided a Microsoft certified Catalyst driver referenced as Catalyst 7.1

There are also unofficial drivers available such as the Omega drivers, claiming to boost performance when compared to the official Catalyst. These drivers typically consist of mixtures of various driver file versions with some registry variables altered and potentially offer superior performance or quality. They are, of course, unsupported, and as such are not guaranteed to function correctly or quantitatively improve functionality (placebo effect). Some of them also provide modified or patched dll files for hardware enthusiasts to modify their cards (as 9500non-pro and 9500Pro use the same chips, and 9800SE and 9800 use the same chips, some of them can be modified by activating all 8 pixel pipelines).

Windows XP Professional X64

ATI has yet to produce mobile 64 bit drivers for the Windows XP X64 Professional operating system. This may be due to a number of factors - for one, the number of mobile 64-bit processors is rather limited - Turion 64 and Intel Core 2 are both fairly recent processors, and are among the first 64-bit mobile processors. Another factor is that most people use the 32-bit version of Windows XP, due not only to video card driver issues, but other driver compatibility issues as well. Nonetheless, it is possible to obtain a proper driver for this type of setup. In order to do so, one requires the use of an unsupported application: ModtoolV4 which can be found here. ModtoolV4 is a 3rd party utility which modifies recent desktop Radeon drivers to work with Mobility Radeon graphics cards (works with Catalyst Control Centre 7.1 - not working with 7.2). Thus, one can download the 64-bit Radeon Catalyst Control Center from ATI's website - running the install program and cancelling the operation is followed by running ModtoolV4 and selecting the folder where the Catalyst Control Center and driver were extracted. After execution, the setup for the driver and Catalyst Control Center occurs automatically.

Macintosh

ATI used to only offer driver updates for their retail Mac video cards, but now also offer drivers for all ATI Mac products, including the GPUs in Apple's portable lines. Apple also includes ATI driver updates whenever they release a new OS update. ATI provides a preference panel for use in Mac OS X called ATI Displays which can be used both with retail and OEM versions of their cards. Though it gives more control over advanced features of the graphics chipset, ATI Displays has limited functionality compared to their Catalyst for Windows product. As Microsoft does not license DirectX for other OS platforms, Mac OS X uses OpenGL exclusively, though in the past with OS 9, Apple used the now-defunct RAVE API.

Linux

Initially, ATI did not produce Radeon drivers for Linux, instead giving hardware specifications and documentation to Direct Rendering Infrastructure (DRI) developers under various non-disclosure agreements. ATI has in mid 2004, however, started to support Linux (XFree86, X.Org), hiring a new Linux driver team to produce fglrx. Their new proprietary Linux drivers, instead of being a port of the Catalyst drivers, were based on the Linux drivers for the FireGL (the FireGL drivers worked with Radeons before, but didn't officially support them), a card geared towards graphics producers, not gamers; though the display drivers part is now based on the same sources as the ones from Windows Catalyst since version 4.x in late 2004. The frequency of driver updates increased in late 2004, releasing Linux drivers every 2 months, half as often as their Windows counterparts. Then since late 2005 this has been increased to monthly releases, inline with the Windows CATALYST releases. On April 12, 2006, ATI released binary drivers for the ATI R5x0 chips (x1300/x1600/x1800 cards), approximately six months after first releasing these cards. As of the 8.25.18 proprietary Linux driver release R200 support is completely broken. There has been no comment from ATI on the problem.

The efforts to provide free drivers for these cards continue, though. The proprietary Linux drivers don't support the R100 chips (Radeon 7000-7500). While the R100 and R200-series chipset drivers were written using specifications provided by ATI (r200 driver), the R300-R500 hardware acceleration was written through reverse engineering (r300 driver) the methods used by ATI's proprietary driver. The reverse-engineered code is now in X.Org and Mesa, bringing experimental support for some of the current Radeon cards. All r3xx cards and all r4xx excluding the Xpress integrated chips should be supported by the new experimental r300 driver. With the 2.6.17 kernel, some cards from the r300 driver were added to the radeon driver.

FreeBSD

FreeBSD systems have the same open-source support for Radeon hardware as Linux, including 2D and 3D acceleration for Radeon R100, R200, and R300-series chipsets. The R300 support, as with Linux, remains experimental due to being reverse-engineered from ATI's proprietary drivers.

ATI does not support its proprietary fglrx driver on FreeBSD, it has been partly ported by a third party as of january 2007. This is in contrast to its main competitor, NVIDIA, which has periodically released its proprietary driver for FreeBSD since November 2002. In the meantime the release is similar to Linux.

BeOS

Although ATI does not provide its own drivers for BeOS, it provides hardware and technical documentation to the Haiku Project who provide drivers with full 2D and video in/out support. They are the sole graphics manufacturer in any way still supporting BeOS.