Radeon HD 4000 Series

The Radeon R700 is the engineering codename for a graphics processing unit series developed by Advanced Micro Devices under the ATI brand name. The foundation chip, codenamed RV770, was announced and demonstrated on June 16, 2008 as part of the FireStream 9250 and Cinema 2.0 initiative launch media event,^[1] with official release of the Radeon HD 4800 series on June 25, 2008. Other variants include enthusiast-oriented RV790, mainstream product RV730, RV740 and entry-level RV710.

Its direct competition was nVidia's GeForce 200 series, which launched in the same month.

Architecture

Execution units

The RV770 extends the R600's unified shader architecture by increasing the stream processing unit count to 800 units (up from 320 units in the R600), which are grouped into 10 SIMD cores composed of 16 shader cores containing 4 FP MADD/DP ALUs and 1 MADD/transcendental ALU. The RV770 retains the R600's 4 Quad ROP cluster count;, however, they are faster and now have dedicated hardware-based AA resolve in addition to the shader-based resolve of the R600 architecture. The RV770 also has 10 texture units, each of which can handle 4 addresses, 16 FP32 samples, and 4 FP32 filtering functions per clock cycle.^[2]

The SPU count of other variants of Radeon R700 family are as follows:

Memory and internal buses

RV770 features a 256-bit memory controller and is the first GPU to support GDDR5 memory, which runs at 900 MHz giving an effective transfer rate of 3.6 GHz and memory bandwidth of up to 115 GB/s. The internal ring bus from the R520 and R600 has been replaced by the combination of a crossbar and an internal hub.^[3]

Multimedia features

The RV770 GPU saw the implementation of UVD 2 (available on Windows operating system at release, available on Linux as of Catalyst 8.10 (implemented via XvBA), and available in the Linux open-source drivers as of kernel 3.10 in combination with Mesa 9.1 (exposed via the widely adopted VDPAU)^[4]), offering full hardware MPEG-2, H.264/MPEG-4 AVC and VC-1 decoding and the support for dual video streams, the Advanced Video Processor (AVP) also saw an upgrade with DVD upscaling capability and dynamic contrast feature. The RV770 series GPU also supports xvYCC color space output and 7.1 surround sound output (LPCM, AC3, DTS) over HDMI. The RV770 GPU also supports an Accelerated Video Transcoding (AVT) feature, which has video transcoding functions being assisted by the GPU, through stream processing.

GPU interconnect enhancements

R700 inter-GPU communications architecture

This generation of dual-GPU design retains the use of a PCI Express bridge, PLX PEX 8647 with a power dissipation of 3.8 watts inclusive of PCI Express 2.0 support, allowing two GPUs on the same PCI Express slot with doubled bandwidth over the past generation of product (Radeon HD 3870 X2). Current generation of dual-GPU design also features an interconnect for inter-GPU communications through the implementation of a CrossFire X SidePort on each GPU, giving extra 5 GB/s full-duplex inter-GPU bandwidth. These two features increase total bandwidth for dual-GPU designs to 21.8 GB/s. At this point, the CrossFire X sideport interconnect has never been enabled in any available drivers.

Variants

Radeon HD 4800

The Radeon HD 4850 was announced on June 19, 2008 while the Radeon HD 4870 was announced on June 25, 2008. They are both based on the RV770 GPU, packing 956 million transistors and being produced on a 55 nm process. The Radeon HD 4850 currently uses GDDR3 memory, while the Radeon HD 4870 uses GDDR5 memory.

Another variant, the Radeon HD 4830 was updated on October 23, 2008, featuring the RV770 LE GPU with a 256-bit GDDR3 memory interface, and 640 shader processors. Basically the RV770 LE is a RV770 with some functional units disabled.

Dual GPU products using two RV770 GPUs, codenamed R700, were also announced. One product named Radeon HD 4870 X2, featuring 2×1GB GDDR5 memory, was released on August 12, 2008, while another dual-GPU product, the Radeon HD 4850 X2, with GDDR3 memory and lower clock speeds, is also available.

A minor update was introduced on April 2, 2009 with the launch of Radeon HD 4890 graphics cards based on the RV790 GPU. Featuring an improved design with decoupling capacitors to reduce signal noise,^[5] altered ASIC power distribution and re-timed the whole GPU chip, which resulted in a slight increase in die size but overall much better stability at high clock rates and a higher default clock. On August 18, 2009, AMD released a stripped down variant of the RV790 GPU called the RV790GT that is used by the Radeon HD 4860 which is now available in all markets.

Radeon HD 4700

ATI Radeon HD 4770

The Radeon HD 4700 series was announced on April 28, 2009. The Radeon HD 4770, is based on the RV740 GPU, packs 826 million transistors and being produced on the latest 40 nm process. The Radeon HD 4730 was introduced June 8, 2009, unlike the RV740 based Radeon HD 4770, the 4730 is a stripped down 55 nm RV770 GPU, named the RV770CE. The 4730 packs 956 million transistors, and uses GDDR5 memory on a 128-bit bus. On September 9, 2009, the RV740PRO based Radeon HD 4750 was released exclusively to the Chinese market. The Radeon HD 4750 is based on the 40 nm RV740 of the Radeon HD 4770 but features a lower clock speed and the absence of a six-pin auxiliary power input.

Radeon HD 4600

The Radeon HD 4600 series was announced on September 10, 2008. All variants are based on the RV730 GPU, packing 514 million transistors and being produced on a 55 nm process. The PCIe version 4600 series products do not require external power connectors.^[6][7][8][9] More recently, the AGP version of the 4670 has been released. This does require an external power connector.

Radeon HD 4300/HD 4500

ATI Radeon HD 4550

The Radeon HD 4350 and Radeon HD 4550 were announced on September 30, 2008, both based on the RV710 GPU, packing 242 million transistors and being produced on a 55 nm process. Both products use either GDDR3, DDR3 or DDR2 video memory. AMD claims these two products have maximum of 20 W and 25 W of power consumption under full load, respectively.^[10]

New market strategy

• According to Phil Hester and Dave Orton, the firm has used a new strategy for the graphics market. Future GPU architectures will undergo small updates (presumably a die shrink at fabrication half-nodes, minor architectural changes, improvements to performance and power consumption, probably as well as implementation of newer API support if available) 6 months after first release, meaning the first GPU cores having only a 6-month product cycle. For mainstream and value segments, the product cycle will instead be 12 months without architectural alterations. The planned successor, presumably codenamed the Radeon R800, will be targeted to launch on an even smaller fabrication process than the half-generation, while expecting that the Radeon R800 will be compatible with the next major version of DirectX API both of which are aimed at a 2009 launch.
• AMD is also shifting focus on releasing products. Whereas the old strategy consisted of designing the enthusiast-level GPU and then stripping it down in stages for cheaper models, AMD plans to reverse this strategy and develop foundation GPUs for entry-level and mainstream markets, and then release cards with an extra foundation GPU to increase performance for the enthusiast market.

Chipset table

Radeon R700 (HD 4xxx) Series

¹ Unified shaders : Texture mapping units : Render output units
² The effective data transfer rate of GDDR5 is quadruple its nominal clock, instead of double as with other DDR memory.
³ The TDP is reference design TDP values from AMD. Different non-reference board designs from vendors may lead to slight variations in actual TDP.
⁴ All models feature UVD2 & PowerPlay.

Successors

The R800 (Evergreen) was released as the Radeon HD 5000 series in late September 2009 with the 5870 and 5850 covering the high end segment of the market. The 5770 and 5750 were released in mid October 2009 to cover the performance segment of the market. The 5600 and 5500 series were released in late January, early February 2010 to cover the lower segments of the market. The 5970 was released in late 2009 to cover the ultra high end segment of the market. Northern Islands are the new code name for the Radeon HD 6000 series and they were released in October 2010, starting with the Radeon HD 6870 and the Radeon HD 6850. The next family (Southern Islands) was released in 2011 and are made in 28 nm.

See also

• ATI
• ATI Radeon
• Radeon R600
• Radeon R800
• Radeon HD 2000 Series
• Radeon HD 3000 Series
• Radeon HD 5000 Series
• Radeon HD 6000 Series
• Radeon HD 7000 Series
• Radeon HD 8000 Series
• Radeon Rx 200 Series
• Nvidia GeForce 9 Series
• Nvidia GeForce 200 Series
• Free_and_open-source_device_drivers:_graphics#ATI.2FAMD

References

External links

• ATI Radeon HD 4000 Series: Desktop, Mobile
• techPowerUp! GPU Database