It features unified shaders and is compatible with Direct3D 10.0's Shader Model 4.0 along with OpenGL 2.1. The first product of the line, the Radeon HD 2900 XT, was launched on May 14, 2007, with variants for other market segments and a half-generation update (RV670), sporting Direct3D 10.1 and Shader Model 4.1 support, released subsequently throughout 2007 and 2008 with low-end and mainstream variants.
The new unified shader functionality is based upon a Very long instruction word (VLIW) architecture in which the core executes operations in parallel. The R600 uses 64 superscalar unified shader clusters, each consisting of 5 stream processing units for a total of 320 stream processing units. The RV610 and RV630 variants have some of the shaders removed from the array, containing a total of 40 (5x8) and 120 (5x24) stream processors, respectively. Each of the first 4 stream processing units is able to retire a finished single precision floating point MAD (or ADD or MUL) instruction per clock, dot product (dp, and special cased by combining ALUs), and integer ADD. The fifth unit is more complex and can additionally handle special transcendental functions such as sine and cosine. Each of the 64 shader clusters can execute 6 instructions per clock cycle (peak), consisting of 5 shading instructions plus 1 branch .
Notably, the VLIW architecture brings with it some classic challenges inherent to VLIW designs, namely that of maintaining optimal instruction flow. Additionally, the chip cannot co-issue instructions when one is dependent on the results of the other. Performance of the GPU is highly dependent on the mixture of instructions being used by the application and how well the real-time compiler in the driver can organize said instructions.
This unit is reminiscent of ATI's earlier "TruForm" technology, used initially in the Radeon 8500, which performed a similar function in hardware. While this tessellation hardware is not part of the current OpenGL or Direct3D requirements, and competitors such as the GeForce 8 series lack similar hardware, Microsoft has included Tessellation as part of their D3D10.1 future plans. The "TruForm" technology from the past received little attention from software developers and was only utilized in a few game titles (such as Madden NFL 2004, Serious Sam, Unreal Tournament 2003 and 2004, and unofficially Morrowind), because it was not a feature shared with NVIDIA GPUs which had a competing Tessellation solution using Quintic-RT patches which met with even less support from developers. Since the Xenos contains similar hardware, and Microsoft sees hardware surface tessellation as a major GPU feature with proposed implementation of hardware tessellation support in future DirectX releases (presumably DirectX 11), dedicated hardware tessellation units may receive increased developer awareness in future titles. It remains to be seen whether ATI's implementation will be compatible with the eventual DirectX standard.
Anti-aliasing capabilities are more robust on R600 than on the R520 series. In addition to the ability to perform 8× MSAA, up from 6× MSAA on the R300 through R580, R600 has a new "custom filter anti-aliasing" (CFAA) mode. CFAA refers to an implementation of non-box filters that look at pixels around the particular pixel being processed in order to calculate the final color and anti-alias the image. This feature is performed by shader processing, instead of entirely in the ROPs, as anti-aliasing has traditionally been implemented. This brings greatly enhanced programmability because the filters can be customized, but may also bring potential performance issues because of the use of shader resources. As of launch of R600, CFAA utilizes wide and narrow tent filters. With these, samples from outside the pixel being processed are weighted linearly based upon their distance from the centroid of that pixel, with the linear function adjusted based on the wide or narrow filter chosen.
Internal functional units of R600 core are connected by an internal 1024-bit bi-directional ring bus (512-bit read and 512-bit write) which wraps around the processor. The ring bus connects at various points to the external memory chips via 8 64-bit memory channels for a total bus width of 512-bits on the 2900 XT. The large bus width allows the 2900 XT to use lower clocked memory while still giving a large amount of memory bandwidth.
The later members, RV630 and RV610 as well as the half-generation update RV670, RV635 and RV620, feature ATI's Unified Video Decoder for hardware decoding for MPEG4 and VC-1 video streams, which itself being the major part of AVIVO HD technology. In terms of functionality, NVIDIA's Purevideo 2 offer similar hardware video-acceleration, with UVD going one step further thanks to greater VC-1 offloading.
All Radeon HD 2000/3000 series graphics cards support native CrossFire. CrossFire efficiency has improved with the R600 core and shows performance approaching the theoretical maximum of twice the performance of a single card.
While some of the architecture of R600 is similar to Xenos, R600 does not feature the embedded DRAM (eDRAM) frame buffer used with Xenos. Xenos' eDRAM is designed tightly around the limited resolutions at which the Xbox 360 operates. Personal computers operate at maximum efficiency at a much wider range of resolutions, which would require a significantly larger amount of eDRAM to be effective.
The R600 family Instruction Set Architecture guide was released on June 11, 2008.
The desktop product lineup was refreshed as the arrival of the performance market-oriented Radeon HD 3800 series based on the "die shrink" version of R600 on a 55 nm process. Two variants, the Radeon HD 3850 and the 3870, became available mid-November 2007. An enthusiast variant, the Radeon HD 3870 X2, with two RV670 cores on single PCB, was launched on January 28, 2008.
Further, the half-generation refresh will span to the mainstream and value market with the codenamed RV635 and the RV620 GPU cores, based on the die shrink version of the RV630 and the RV610 cores, on 55 nm fabrication process.
An odd variant, the Radeon HD 3690, was released early February 2008 for the China market only. What makes it odd is the GPU core it carries. The Radeon HD 3690 is actually based on an RV670 core with half of the memory interface bit width and memory amount to that of an Radeon HD 3850/3870 graphics card. A further announcement was made that there will be an Radeon HD 3830 variant bearing the same features as Radeon HD 3690, but with unique device ID and does not allow add-in card partners in China to re-enable the burnt out portion of the GPU core for more memory bandwidth.
The Mobility Radeon HD 2300 is a value product which includes UVD "in silica" but lacks unified shader architecture and DirectX 10.0 / SM 4.0 support, limiting support to DirectX 9.0c / SM 3.0 using the more traditional architecture of the previous generation. A high-end variant, the Mobility Radeon HD 2700, with higher core and memory frequencies as the Mobility Radeon HD 2600 was released in mid-December 2007.
The Mobility Radeon HD 2400 is offered in two model variants; the standard HD 2400 and the HD 2400 XT.
The Mobility Radeon HD 2600 is also available in the same two flavours; the plain HD 2600 and at the top of the current mobility lineup the HD 2600 XT.
The half-generation update treatment had also applied to mobile products. Announced prior to CES 2008 is the Mobility Radeon HD 3000 series. Planned to be released in the first quarter of 2008, the Mobility Radeon HD 3000 series consists of two families, the Mobility Radeon HD 3400 series and the Mobility Radeon HD 3600 series, all featuring DirectX 10.1 support while the GPU was made on 55 nm process. The Mobility Radeon HD 3600 series also features industry's first implementation of 128-bit GDDR4 memory on-board.
About the time of late March to early April, 2008, AMD renewed the device ID list on its website with the inclusion of Mobility Radeon HD 3850 X2 and Mobility Radeon HD 3870 X2 and their respective device IDs. Later in Spring IDF 2008 held in Shanghai, a development board of Mobility Radeon HD 3870 X2 was demonstrated alongside a Centrino 2 platform demonstration system. The Mobility Radeon HD 3870 X2 are based on two M88 GPUs with the addition of a PCI Express switch chip on a single PCB. The demonstrated development board is on PCI Express 2.0 x16 bus, while the final product is expected to be on AXIOM/MXM modules.
The R600 core used in the HD 2900 lacks the ATI Unified Video Decoder (UVD) required for hardware acceleration of certain types of HD video. Nonetheless, the card is fully capable of playing any HD video format; however, shaders are utilized for the decoding process. Initially there was much confusion as to whether or not the product included dedicated video processor hardware, due in part to statements that it supported the software program AVIVO HD. Many reviewers and subsequent readers/consumers interpreted this as meaning the HD2900 incorporated the same UVD hardware as found in the HD 2400 & HD 2600 series, despite some sites noting this difference at launch time, weeks before the issue first gained traction as a result of a TechReport article. This confusion and subsequent discussions prompted AMD to make a formal statement designed to clarify exactly what UVD was available in which models. The HD 2900 XT video playback capabilities are similar to those of the previous X1000 cards with AVIVO capabilities.
Starting August, 2007 some system builders including Falcon Northwest received the 1 GB GDDR4 (with Samsung 0.9 ns (K4U52324QE-BC09) GDDR4) version of the Radeon HD 2900 XT. This was incorrectly referred to as the "Radeon HD 2900 XTX".
Variants of the series include the Radeon HD 2900 Pro and the Radeon HD 2900 GT. The Radeon HD 2900 Pro uses the same R600 GPU, but is clocked lower at 600 MHz core and 800 MHz memory (1600 MHz effective). This variant is configured with 512 MB or 1 GB (GDDR3/GDDR4) of video memory and the same 512-bit memory controller as the Radeon HD 2900 XT instead of the previously rumoured 256-bit memory controller. The Radeon HD 2900 GT is a 240 stream processor variant clocked the same as the HD 2900 Pro with 256 MB of video memory on a 256-bit interface.
Another variant incorporates two RV630 cores onto a single PCB with a PCI-E bridge splitting the PCI-E x16 bandwidth into two groups of PCI-E x8 lanes (each 2.0 Gb/s). This functionally provides a CrossFire configuration on one video card with a total of four DVI output (HDMI output via dongle) with HDCP. AMD calls this product the "Radeon HD 2600 X2" as seen by some vendors and as observed inside the INF file of Catalyst 7.9 version 8.411. Sapphire and other vendors including PowerColor and GeCube have either announced or demonstrated their respective "Crossfire on a card" products. Catalyst 7.9 added support for this hardware in September 2007. However, AMD did not provide much publicity to promote it. A vendor may offer cards containing 256 MB, 512 MB, or 1 GB of video memory. Although the memory technology utilized is at a vendor's discretion, most vendors have opted for GDDR3 and DDR2 due to lower manufacturing cost and positioning of this product for the mainstream rather than performance market segment.
Reports has that the first batch of the RV610 core (silicon revision A12), only being released to system builders, has a bug that hindered the UVD from working properly, but other parts of the die operated normally. Those products were officially supported with the release of Catalyst 7.10 driver, which the cards were named as Radeon HD 2350 series.
The Radeon HD 3800 series is based on the RV670 graphics chip, manufactured on a 55 nm fabrication process with 256-bit memory controller, die size at 192 mm² and packed with 666 million transistors, with the same 320 Stream Processing Units as the R600 core. The Radeon HD 3000 series supports DirectX 10.1 and Shader Model 4.1 with double-precision floating-point operations support, the UVD has also been implemented on-die, providing full hardware decoding of VC-1 and H.264 video streams. AMD claims that the support of DirectX 10.1 can bring improved performance and processing efficiency with reduced rounding error (0.5 ulp compared with average error 1.0 ulp as tolerable error), better image details and quality, global illumination, a technique used in many animated films such as Shrek 3, and more improvements to consumer gaming systems therefore giving more realistic gaming experience. Further, the Radeon HD 3800 series also sees the implementation of power state controller as well as the PowerPlay technology for the desktop graphics, allowing Catalyst Control Center to monitor GPU utilizations and further reduce power draw of the graphics by switching states of the GPU core for different usage scenarios with different performance settings.
The Radeon HD 3800 series has one more variant, the Radeon HD 3870 X2 (codenamed R680) released on January 28, 2008, featuring two RV670 cores with a maximum of 1024 MiB GDDR3, targeting the enthusiast market and replacing the Radeon HD 2900 XT, the card implements ATI PowerPlay technology to reduce power consumption and digital PWM, to provide steady current for each GPU core. The card is able to achieve a peak single-precision floating point performance of just over 1 TFLOPS, at 1.06 TFLOPS, being the world's first single-PCB graphics product breaking the 1 TFLOP mark.
The Radeon HD 3870 X2 uses the same approach for communications between the two GPU cores as the previous generations of products, the Sapphire Radeon X1950 Pro Dual and the Radeon HD 2600 X2, the two GPU cores were able to communicate to each other through an onboard PCI-E switch, providing each core with x8 (Radeon X1950 Pro Dual) to x16 (Radeon HD 2600 X2) PCI-E bandwidth and becoming a software CrossFire setup and thus allow to plug in two hardware CrossFire bridges. While the Radeon HD 3870 X2 will implement PEX8547 PCI-E switch, each core sharing x16 PCI-E bandwidth, the card will only see one CrossFire bridge being placed onboard and between the cores, thus only allows one CrossFire bridge to be plugged onto the card.
AMD stated the possibility that the Radeon HD 3870 X2 of supporting four card CrossFire, to reach 8 GPU scalability on several motherboards, including the MSI K9A2 Platinum and Intel D5400XS, due to the fact that these motherboards have sufficient spaces between PCI-E slots for dual-slot cooler video cards, presumably as a combination of two separate hardware CrossFire setups with a software CrossFire setup bridging the two, but currently with no driver support.
|Product Category|| Model number |
range (steps of 10)1
| Price range |
| Shader amount |
|Type|| Width |
|800 X2-990 X23||>$250||200%|| GDDR3,|
|2x 256-bit||512/1024|| 2 DVI, |
HDMI, DP (Dongle)
|HD 3870 X2/HD 3850 X2|
|256-bit||256/512/1024|| 2 DVI, |
HDMI, DP (Dongle)
|Mainstream||600-790||$100–$150||37.5-75%|| DDR2, |
|128-bit||128/256/512|| D-Sub, DVI||HD 3650, HD 3690|
|DVI, 2 DP, |
|Budget/Value||350-590||<$99||25-50%|| DDR2, |
|64-bit|| 64/128 |
| D-Sub, DVI, |
HDMI, DP (Dongle)
|IGP||000-300||N/A||25-50%|| UMA, |
| UMA + 32-bit |
| 64/1284 + UMA |
| D-Sub, DVI, |
| X1270/X1250/X1200 |
HD 3200/HD 3100/2100
Other features including the implementation of Direct3D 10.1, AVIVO HD with second generation of UVD and hardware surface tessellation. One variant, the Radeon HD 3650 was released on January 23, 2008. Reference design with dual DisplayPort and single DVI-D port was revealed .
One of the notable features is that the Radeon HD 3400 series (including Mobility Radeon HD 3400 series) video cards support ATI Hybrid Graphics.
Two variants, the Radeon HD 3450 and Radeon HD 3470 were released on January 23, 2008.
The Purple Pill tool issue, which could allow unsigned drivers to be loaded into Windows Vista and tamper with the operating system kernel, was resolved in the Catalyst 7.8 release (version 8.401). The AVIVO video converter for Windows Vista, and color temperature control in Catalyst Control Center was added with the release of Catalyst 7.9, package version 8.411. Software CrossFire was enabled for HD 2600 and HD 2400 series video cards with the release of Catalyst 7.10 (package version 8.421)
The Catalyst 8.1, package version 8.451, supports for MultiView technology for accelerated OpenGL rendering on multiple video card setup (CrossFire). The driver also allows CrossFire configurations for Radeon HD 3850 and HD 3870 video cards.
The Catalyst 8.3 is described by AMD as a milestone release, supporting DirectX 10.1, ATI CrossFire X technology and allowing the mixing of different Radeon HD 3800 series video cards to form a CrossFire X setup with 2 to 4 GPUs. Catalyst 8.3 introduced to new video controls to further enhance the video playback quality, these controls includes edge enhancement and noise reduction settings. There is also the support for extended desktop in CrossFire X mode. The anti-aliasing support for Unreal Engine 3.0 in DirectX 9.0 games, support for CFAA filters (wide tent and box tent) to be enabled when Super AA is enabled, and other features as developer support for Hardware surface tessellation, hardware accelerated wide aspect ratio LCD scaling, HydraVision support for Windows Vista allowing to add maximum 9 virtual desktops and new Folding@Home client (version 6.10) are also officially supported in this release.
The Catalyst 8.5, package version 8.493 brought new features include component video with 480i and 480p resolutions, SECAM TV output support, 1080p HDTV custom mode via HDMI, 1080p24 (1080p resolution at 24 fps) support, HDMI Audio for non-standard TV modes (CEA 861b), support for adaptive anti-aliasing under OpenGL, Windows XP SP3 support and un-install utility enhancements. The driver also includes performance improvements and fixes some instability issues and rendering issues on some games.
Note that Catalyst drivers 7.10, 7.11 and 7.12 do not yet support the AGP versions of Radeon HD 2000 series cards with RIALTO bridge. Installing Catalyst drivers 7.10, 7.11 or 7.12 on those cards will yield the following error message: "setup did not find a driver compatible with your current hardware or operating system." or simply fail outright. The AGP cards in question are supported unofficially by ATI/AMD with a "hotfixed" Catalyst driver-set each month since May 2008 with the Catalyst 8.5 hotfix . Their PCI vendor IDs are listed below:
|GPU core||Product||PCI device ID|
|RV610||Radeon HD 2400 Pro||94C4|
|RV630||Radeon HD 2600 Pro||9587|
|RV630||Radeon HD 2600 XT||9586|
Another Linux driver is the RadeonHD driver, an open-source ATI R500/600 display driver, it is developed in part by specifications that AMD has openly published. To date, AMD has released register specifications for M56, M76, RV630 and RS690 GPUs and 3D programming guide for the R600, R500, and R300 family of GPUs. AMD has committed to releasing their R500 and R600 GPU documentation along with publishing their specifications for past generations of GPUs.