ATi X1900XT Graphics Card

After years of playing catch-up to NVIDIA, the Red team finally has a product that beats NVIDIA hands down with its R580 architecture and Ultra Threaded Dispatch Processor ATi X1900XT Graphics Card

Friday, March 10, 2006

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Price: Not yet launched

Meant For: Extreme gamers

Key Specs: 625 MHz, 512 MB 1.45 GHz GDDR3, 48 pixel processors, 8 vertex shaders

Pros: Dual DVI output, crossfire-enabled

Cons: None

Contact: Mediatech India.Tel: 9873186855E-mail: haresh@mediatechindia.com  RQS# E24 or SMS 130324 to 9811800601

After years of playing catch-up to NVIDIA, the Red team finally has a product that beats NVIDIA hands down with its R580 architecture and Ultra Threaded Dispatch ProcessorIt's been quite long since ATi was anywhere near the top spot in PC graphics. The spot was earlier dominated by NVIDIA. Despite the new core, the R580 is not that big a departure from the R520, but has still managed to throw NVIDIA off the pedestal it has monopolized for so long. We got a reference card from ATi, so there was nothing bundled. Retail might be different. The card in itself looks really bulky, has two DVI out-ports and an S-Video out.

R580 architecture
Along with eight vertex shaders, the card has been endowed with 48-independent pixel shader processors compared to 24 on the 7800GTX-512. Why so many? Its because of the way games have evolved. When shaders were introduced in graphic cards, people had to spend huge amounts to buy a one that had just 32 MB RAM! Games were just beginning to exploit the potential of the pixel shader technology. The other important thing is the use that these shaders were being put to. Rendering a graphic requires two kinds of operations-texture and arithmetic. Earlier the ratio between these was 1:1. However, most games today require the operations to be performed  in a 5:1 ratio.  There is also a technique called Procedural Textures that allows you to perform most shader operations mathematically. Finally, texture operations depend more on the memory bandwidth, size, speed, and not so much on the pixel or vertex pipelines. To increase these, you really need to update the whole system. Arithmetic operations, on the other hand, are mere calculations. Thus, more the processors,  the faster arithmetic operations can be performed. Since 5 out of 6 operations today are arithmetic, having more processors would obviously lead to a huge performance boost. This is what ATi has done. By increasing the number of pixel processors from 16 to 48, it has essentially tripled the capabilities.

The Ultra Threaded Dispatch Processor acts as an arbiter and ensures that each shader processor has got work to do. It keeps re-orderingthe instructions for optimal performance. We suspect that the entire architecture is out of order execution friendly. This is important since ATi is constantly pushing towards making GPUs which can take some of the load off the processor. Using our standard test bed (Athlon X2 4800+, 1GB RAM, A8N-SLI board and 7200RPM 120GB SATA drive), we ran the tests at the absolute maximum settings. The card comfortably outdid the 7800GTX-512 in every test except Quake 4, where, the 7800GTX-512 outdid it consistently. This is perhaps a driver bug or maybe the NVIDIA  cards just love the Quake 4 engine. However, every time we cranked up the image quality levels, ATi got away from NVIDIA faster. This is certainly because of the 48 pixel shaders the card has.

Bottom Line A brilliantly fast card and without a doubt. It will satisfy all your gaming needs. The only thing faster will probably be the X1900XTX. We expect the 1900XT to be priced around35k which almost classifies this as a value buy!

Varun Dubey

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