iXBT Labs - ATI RADEON HD 4670 512MB Graphics Card - Page 1: Introduction, specifications

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Introduction

It's been long since we published the last baseline review of Low-End solutions. Such graphics cards have been considered ill-suited for modern games, often failing to provide acceptable performance even at moderate quality settings. But time passes and everything changes. Not long ago competition made it possible to launch powerful Lower Mid-End solutions (like Radeon HD 3850 and GeForce 9600 GT). And now it's Low-End time.

You must understand that it's not only about gradual graphics card performance growth. It is natural industry development. Consoles have a strong impact on game projects these days, and most new titles are actually multiplatform, developed simultaneously for PC, Xbox 360 and PS3.

Unlike PCs, consoles are naturally limited to a single configuration. So, in a couple of years, their 3D performance will start to lag behind inexpensive computers. Even new Low-End graphics cards can provide enough processing power for multiplatform games. Higher performance of expensive graphics cards is often spent on higher resolutions, antialiasing and better texture filtering. And on rare exclusive PC titles like Crysis and S.T.A.L.K.E.R.: Clear Sky.

Today we'll examine new Low-End solutions from AMD, which can provide acceptable performance in most games for a relatively small price. All these solutions and GPUs are based on the RV7xx architecture, also a foundation for the popular RADEON HD 4800 series. For now, in the practical part of this review we'll focus on the fastest RV730-based card. But we'll also provide specifications of slower cards.

Before you read this article, you may want to study these baseline theoretical articles, which describe various features of graphics cards and architectural peculiarities of older products from NVIDIA and AMD.

These articles predicted the current situation with GPU architectures, and confirmed many of our assumptions about future solutions. The detailed information about AMD RV7xx and R6xx unified architectures is provided in these articles:

OK, now let's examine detailed characteristics of new RADEON HD 4600/4500 graphics cards, based on the new RV730/RV710 GPUs.

RADEON HD 4600 series

Code name: RV730
Fabrication process: 55 nm
514 million transistors
Unified architecture with an array of common processors for streaming processing of vertices and pixels, as well as other data
Hardware support for DirectX 10.1, including new Shader Model 4.1, geometry generation, and stream output
128-bit memory bus: two 64-bit controllers supporting DDR2/DDR3/GDDR2/GDDR3 memory
Core clock: 600-750 MHz
8 SIMD cores, including 320 scalar floating-point ALUs (integer and floating-point formats, support for FP32 and FP64 in compliance with IEEE 754)
8 enlarged texture units supporting FP16 and FP32 formats
32 texture address units
128 texture fetch units
32 bilinear filtering units that can filter FP16 textures at full speed, trilinear and anisotropic filtering for all texture formats
Dynamic branching in pixel and vertex shaders
8 ROPs supporting antialiasing with programmable sample patterns (over 16 samples per pixel), including FP16 or FP32 formats of the frame buffer. Peak performance is up to 8 samples per cycle (including MSAA 2x/4x and FP16 buffers), 32 samples per cycle in Z only mode
Writing results up to eight frame buffers simultaneously (MRT)
Integrated support for two RAMDACs, two Dual Link DVIs, HDMI, HDTV, DisplayPort

RADEON HD 4670

Core clock: 750 MHz
Unified processors: 320
32 texture units, 8 blending units
Effective memory frequency: 2000 MHz (2*1000 MHz)/1800 MHz
Memory type: GDDR3/DDR3
Memory: 512/1024 MB
Memory bandwidth: 32.0/28.8 GB/sec
Maximum theoretical fillrate: 6.0 gigapixel per second
Theoretical texture sampling rate: 24.0 gigatexel per second
Two CrossFireX connectors
PCI Express 2.0 x16
2 x DVI-I Dual Link, 2560x1600 video output
TV-Out, HDTV-Out, support for HDCP, HDMI, DisplayPort
Power consumption: below 75 W (without additional power connectors)
Single-slot design
Recommended price: $79

RADEON HD 4650

Core clock: 600 MHz
Unified processors: 320
32 texture units, 8 blending units
Effective memory frequency: 1000 MHz (2*500 MHz)
Memory type: DDR2
Memory: 512 MB
Memory bandwidth: 16.0 GB/sec
Maximum theoretical fillrate: 4.8 gigapixel per second
Theoretical texture sampling rate: 19.2 gigatexel per second
Two CrossFireX connectors
PCI Express 2.0 x16
2 x DVI-I Dual Link, 2560x1600 video output
TV-Out, HDTV-Out, support for HDCP, HDMI, DisplayPort
Power consumption: below 60 W (without additional power connectors)
Single-slot design
Recommended price: $69

RADEON HD 4500 series

Code name: RV710
Fabrication process: 55 nm
242 million transistors
Unified architecture with an array of common processors for streaming processing of vertices and pixels, as well as other data
Hardware support for DirectX 10.1, including new Shader Model 4.1, geometry generation, and stream output
64-bit memory bus: one 64-bit controller supporting DDR2/DDR3/GDDR2/GDDR3 memory
Core clock: 600 MHz
2 SIMD cores, including 80 scalar floating-point ALUs (integer and floating-point formats, support for FP32 and FP64 in compliance with IEEE 754)
2 enlarged texture units supporting FP16 and FP32 formats
8 texture address units
32 texture fetch units
8 bilinear filtering units that can filter FP16 textures at full speed, trilinear and anisotropic filtering for all texture formats
Dynamic branching in pixel and vertex shaders
4 ROPs supporting antialiasing with programmable sample patterns (over 16 samples per pixel), including FP16 or FP32 formats of the frame buffer. Peak performance is up to 4 samples per cycle (including MSAA 2x/4x and FP16 buffers), 16 samples per cycle in Z only mode
Writing results up to eight frame buffers simultaneously (MRT)
Integrated support for two RAMDACs, two Dual Link DVIs, HDMI, HDTV, DisplayPort

RADEON HD 4550

Core clock: 600 MHz
Unified processors: 80
8 texture units, 4 blending units
Effective memory frequency: 1600 MHz (2*800 MHz)
Memory type: DDR3
Memory: 256/512 MB
Memory bandwidth: 14.4 GB/sec
Maximum theoretical fillrate: 2.4 gigapixel per second
Theoretical texture sampling rate: 4.8 gigatexel per second
PCI Express 2.0 x16
2 x DVI-I Dual Link, 2560x1600 video output
TV-Out, HDTV-Out, support for HDCP, HDMI, DisplayPort
Power consumption: below 25 W (without additional power connectors)
Single-slot design, passive cooling
Recommended price: $29-35

AMD continues to manufacture 55nm graphics solutions, time has come for Low-End RV7xx GPUs. Compared to the 65nm fabrication process, still widely used by NVIDIA, this fabrication process gives the following advantages: smaller die, higher frequency potential, and better yield of good GPUs, which can operate at the required frequencies. It all results in lower prime costs. Like the previous RV770 solutions, the new GPUs are very efficient as far as power consumption and performance per die surface area are concerned.

These solutions are marked in the same style as HD 3000 cards, only the first digit has changed. Positioning of HD 4650 matches that of HD 3650 at the time this series was rolled out. And the new HD 4670 and HD 4550 solutions will take up intermediate positions in the series. As RV730 and RV710 were designed to replace older AMD series, they will gradually push out the HD 3000 series.

As is always the case with AMD, HD 4670 and 4650 cards differ in GPU/memory clock rates. But it's not the only difference between these cards -- the 4670 card comes with GDDR3 or new DDR3 memory of higher volume, and the 4650 card is equipped with DDR2 memory. Besides, the 4670 model consumes more power and has a tad higher recommended price. We'll have to examine real retail prices though.

Memory capacity of Low-End cards has always depended on its type. Inexpensive DDR2 or DDR3 memory is usually installed in higher volumes. Minimum memory volume of the HD 4600 solution is 512 MB. It's very good, because modern games have high memory requirements and usually use 500-600 MB or even more (in rare cases). 512 MB of memory is currently the optimal memory volume for Low- and Mid-End graphics cards. And only the cheapest HD 4550 card has a 256-MB DDR3 modification, which is justified for a card of such level.

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