Graphics Cards Guide

ATI Radeon HD 2900 XT 512MB (Reference Card) review

ATI Radeon HD 2900 XT 512MB (R600)

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ATI's Heavyweight Waddles in

ATI's Heavyweight Waddles in

The long suffering legions of ATI fans will finally have something to smile about, as ATI's new DirectX 10 series of graphics cards based on its R600 core are released today. Plagued by production delays that led to incessant speculation about its fate, this new architecture has been pushed back numerous times in the past. This dismal state of affairs culminated in NVIDIA trumping ATI with its DirectX 10 GeForce 8 graphics cards last November, when all eyes were predictably on ATI, which had earlier came up with the first unified shader graphics architecture - the Xenos chip found on the Xbox 360. As the unified shader architecture better facilitates and suits the functionality offered from DirectX 10, it must have been galling for ATI to be beaten to the punch by NVIDIA when it mattered most.

Nevertheless, these new graphics cards, newly christened as the Radeon HD 2000 series, are finally here after such a long and difficult gestation. Consisting of three major SKUs (with the typical loss of functional units descending from the high-end to low) and corresponding to the enthusiast, mainstream and value segments, they are respectively, the Radeon HD 2900, the HD 2600 and the HD 2400 series.

Despite hopes that ATI will pull off a simultaneous and complete product launch inclusive of mainstream and budget options, something which the company hinted at previously when announcing the delay of the R600 , ATI was realistically able to launch the flagship HD 2900 series today, which currently has only one representative, the Radeon HD 2900 XT 512MB. The specifications of the other Radeon HD series have been released to the press however, though one would need to wait till late June before these mainstream variants are available for retail (and benchmarking). Similarly, information about the Mobility Radeon versions of the HD 2000 series have also been disseminated but the earliest consumers can expect from to find these energy-saving chipsets is July. Therefore, we will only be concentrating on the Radeon HD 2900 XT today, along with some of the general architectural innovations on the R600. Details of the other Radeon HD series will be covered in a future article.

The Radeon HD 2900 XT is based on the R600 GPU, which clocks in with a massive transistor count of 700 million. That is only slightly more than the 681 million on NVIDIA's competing G80 core. ATI does use 80nm process technology to manufacture the die compared to the 90nm G80 and plans are already afoot to shrink this further to 65nm. In fact, the HD 2600 and 2400 series are designed for 65nm, though of course they won't be appearing for another month or so. The advantages of doing so include lower power consumption, lower operating temperatures and more importantly for ATI, lower cost of production due to higher yield. As it is, the R600 is rated to consume 215W of power, which is understandably too extreme for many users, especially when NVIDIA's GeForce 8800 Ultra is rated at 175W. By contrast, the 65nm HD 2600 and 2400 cards are expected to consume 45W and 25W respectively.

Instead of dumping all the information about the Radeon HD 2900 XT on you, we have selected some relevant details and compared them against its probable rivals and its predecessor in the table below. Some typical facts that consumers would probably be looking out for include the 742MHz core clock speed, the 1650MHz DDR memory clock and its 512MB memory size operating via a 512-bit wide memory bus.

R600 Compared
Model ATI Radeon HD 2900 XT 512MB NVIDIA GeForce 8800 GTX 768MB NVIDIA GeForce 8800 GTS 640MB ATI Radeon X1950 XTX 512MB
Core Code R600 G80 G80 R580+
Transistor Count 700 million 681 million 681 million 384 million
Manufacturing Process (microns) 0.08 0.09 0.09 0.09
Core Clock 742MHz 575MHz 500MHz 650MHz
Vertex Shaders 64 Shader Processors (consisting of 320 Stream Processing Units in total) 128 Stream Processors 96 Stream Processors 8
Rendering (Pixel) Pipelines 16
Pixel Shader Processors 48
Shader Processor Clock 740MHz 1350MHz 1200MHz 650MHz
Texture Mapping Units (TMU) or Texture Filtering (TF) units 16 64 48 16
Raster Operator units (ROP) 16 24 20 16
Memory Clock 1650Hz DDR3 1800MHz DDR3 1600MHz DDR3 2000MHz DDR4
DDR Memory Bus 512-bit 384-bit 320-bit 256-bit
Memory Bandwidth 105.6GB/s 86.4GB/s 64.0GB/s 64.0GB/s
Ring Bus Memory Controller 1024-bit NIL NIL 512-bit (for memory reads only)
PCI Express Interface x16 x16 x16 x16
Molex Power Connectors Yes (1x 6-pin + 1x 8-pin) Yes (dual) Yes (dual) Yes
Multi GPU Technology Yes (CrossFire) Yes (SLI) Yes (SLI) Yes (CrossFire)
DVI Output Support 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link
HDCP Output Cable? Yes Yes Yes Yes
Street Price ~ US$399 (SRP) ~ US$550 - US$650 US$399 (SRP) ~ US$400