Radeon R700: Wikis

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Radeon HD 4000 series
Codename(s) Wekiva
Makedon (RV770),
Trojan (RV770)[1],
Spartan (R700)[2]
Created in year 2008
Release date 2008
Entry-level cards Radeon HD 4300, HD 4500
Mid-range cards Radeon HD 4600, HD 4700
High-end cards Radeon HD 4800
Enthusiast cards Radeon HD 4800 X2
Direct3D support 10.1, Shader Model 4.1
OpenGL support 3.1
Predecessor Radeon HD 3000 series
Successor Radeon HD 5000 series

The Radeon R700 is the engineering codename for a Graphics Processing Unit series released by AMD Graphics Product Group, sold under the ATI brand. 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 [3], with official release of the HD4800 series on June 25, 2008. Further products including enthusiast-oriented RV790, mainstream product RV730, RV740 and entry-level RV710 products were released throughout 2008 and the first quarter of 2009. Primary competition came from nVidia's Geforce GTX 200 series.

Contents

Architecture

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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/shift/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. [4]

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

Series/Products GPU codename Stream Processing Units (SPU)
Radeon HD 4890 RV790XT 800
Radeon HD 4870 RV770XT
Radeon HD 4860 RV790GT 640
Radeon HD 4850 RV770PRO 800
Radeon HD 4830 RV770LE 640
Radeon HD 4770 RV740
Radeon HD 4750 RV740PRO 480
Radeon HD 4730 RV770CE 640
Radeon HD 4670 RV730XT 320
Radeon HD 4650 RV730PRO
Radeon HD 4550
Radeon HD 4350
RV710 80

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 speed of 3600 MHz 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. [5]

Multimedia features

The RV770 GPU saw the implementation of UVD 2, 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 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 10 GB/s inter-GPU bandwidth (5 GB/s each direction). These two features increase total bandwidth for dual-GPU designs to 21.8 GB/s. At this point, the CrossFire X Sideport isn't enabled by default in the 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 cut-down version of the RV770 GPU used on Radeon HD 4850 and HD 4870 products.

Dual GPU products using two RV770 GPUs, codenamed R700, were also announced. One product named Radeon HD 4870 X2, featuring 2 GB 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, 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. On August 18, 2009, ATI 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. In September 9, 2009, the RV740PRO based Radeon HD 4750 was released exclusively to the Chinese market. The Radeon HD 4750 is based on the 40nm 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 one molex 5V 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 maximums of 20W and 25W 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

Successors

The specifications for the architectures of the R800 and R900 families are "closed", with the specifications of the R1000 family being developed. [11]

See also

References

External links


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