Graphics Cards Guide

Sapphire Radeon HD 2600 XT 256MB GDDR4 review

Sapphire Radeon HD 2600 XT 256MB GDDR4

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Much has already been said and written regarding ATI's new mainstream DirectX 10 graphics cards, the Radeon HD 2600 and 2400 series. To sum up our outlook on these products so far - if you are hoping that these cards will be the saviors that some ATI fans have been fervently praying for, look away. Despite the initial optimism generated by news that these cards were using 65nm cores, 3D performance has turned out to be rather disappointing. Instead, what these cards bring to the table are other, less talked about, though perhaps equally important aspects of a modern graphics card, like its dedicated universal video decoder (UVD) engine and significantly lower numbers for noise, heat and power consumption compared to previous ATI GPUs. Whether that is enough for consumers remains to be seen.

Together with competitive prices that place these Radeon HD cards into lower price brackets compared with NVIDIA's corresponding products (though it could be argued that there is no longer any direct comparison between the two since the ATI cards have looked to be slower in benchmarks), ATI could yet do reasonably well in the mainstream segment where 3DMark scores are not the most important criteria. Since we have already looked at the budget Radeon HD 2400 XT and an overclocked Radeon HD 2600 PRO , it was about time to give some attention to the top model of ATI's new mainstream contingent, the Radeon HD 2600 XT.

As the highest clocked member of the Radeon HD 2600 family, the XT comes with GDDR3 or GDDR4 flavored memory with a maximum rated speed of 2200MHz DDR. The GDDR4 version we're taking a look today comes with Samsung chips that are rated at 0.9ns that allow them to handle the high speeds and at the same time be more power efficient. Meanwhile, the same RV630 core present on all the Radeon HD 2600 cards, along with the exact same number of stream processors, texture units and other graphics hardware, are all found on this card. In short, everything should be identical to the Radeon HD 2600 PRO that we had covered previously, but with vastly higher clock speeds and the use of GDDR4 memory. How would this leading Radeon HD 2600 card stack up against NVIDIA's GeForce 8600 series?

Top Mainstream Graphics Cards from ATI and NVIDIA
GPU/VPU ATI  Radeon HD 2600 XT 256MB GDDR4 NVIDIA GeForce 8600 GTS 256MB NVIDIA GeForce 8600 GT 256MB
Core Code RV630 G84 G84
Transistor Count 390 million 289 million 289 million
Manufacturing Process (microns) 0.065 0.08 0.08
Core Clock 800MHz 675MHz 540MHz
Vertex Shader Pipelines 24 Shader Processors (consisting of 120 Stream Processing Units in total) 32 Stream Processors 32 Stream Processors
Rendering (Pixel) Pipelines
Shader Processor Clock 800MHz 1450MHz 1190MHz
Texture Mapping Units (TMU) or Texture Filtering (TF) units 8 16 16
Raster Operator units (ROP) 4 8 8
Memory Clock 1100MHz (2200MHz GDDR4) 1000MHz (2000MHz DDR3) 700MHz (1400MHz DDR3)
DDR Memory Bus 128-bit 128-bit 128-bit
Memory Bandwidth 35.2GB/s 32.0GB/s 22.4GB/s
Ring Bus Memory Controller 256-bit (for memory reads only) NIL NIL
PCIe Interface x16 x16 x16
Molex Power Connectors NIL Yes NIL
Multi GPU Technology Yes (CrossFire) Yes (SLI) Yes (SLI)
DVI Output Support 2 x Dual-Link 2 x Dual-Link 2 x Dual-Link
HDCP Compliance Yes Yes Vendor Dependent
Estimated Retail Price (US$) ~US$149 ~US$199 ~US$119 - 149