ATI Radeon X1900 XTX And CrossFire: R580 Is Here

Name: ATI Radeon X1900 XTX And CrossFire: R580 Is Here - Page 3
Brand: ATI

by Marco Chiappetta — Tuesday, January 24, 2006, 08:00 AM EDT

The Radeon X1900 (R580) is architecturally very similar to the Radeon X1800 (R520), so we recommend perusing this article for a more comprehensive look at the features common to both GPUs, like the 512-bit Ring Bus Memory Controller, Shader Model 3.0 support and AVIVO.

ATI Radeon X1900 Architectural Overview Diagram

This high level architectural block diagram above highlights the main feature of the Radeon X1900 -- its 48 pixel shader processors. Unlike the Radeon X1800 which has 16 pixel shader processors, and the GeForce 7800 GTX which has 24, the Radeon X1900 has a full 48 pixel shader processors in the first stage of the 3D pipeline.

With the R520, ATI de-coupled the individual stages in the 3D pipeline, which gave them the ability to have an asymmetrical number of pixel shader processors and ROPs, or "Render Backends". So basically, what ATI did with the R580, was take the existing R520 architecture and tripled the number of pixel shader processors in the first stage of the pipeline. But the rest of the chip is largely unchanged. The R580 still has the same 8 vertex shaders, 16 texture units, 16 ROPs, and the same memory controller. The large number of pixel shader processors gives the X1900 a ton of resources for executing pixel shader code, but the in situations where pixel shading is not a limiting factor in performance, the X1900 should perform similarly to the X1800 XT. Just about every new gaming title and many titles released over the last couple of years, make use of pixel shaders however, so the additional 60 million transistors used on the X1900 to increase the number of shader processors should certainly be put to good use, especially with newer gaming titles that make heavy use of longer, more complex shaders.

The pixel shader processors are grouped together in quads. The Radeon X1900 has twelve of these quads for executing pixel shader code. The components of each quad and their respective computational capabilities are outlined above. Over an above the number of pixel shader processors, ATI had made a couple of other advancements with the R580 as well. We'll talk about those changes next.

Tags: ATI, Radeon, Fire, CrossFire, SSF, x1, OS, r580, ATI Radeon, 580, OSS, XT, here, R5, and

Marco Chiappetta

Marco's interest in computing and technology dates all the way back to his early childhood. Even before being exposed to the Commodore P.E.T. and later the Commodore 64 in the early ‘80s, he was interested in electricity and electronics, and he still has the modded AFX cars and shop-worn soldering irons to prove it. Once he got his hands on his own Commodore 64, however, computing became Marco's passion. Throughout his academic and professional lives, Marco has worked with virtually every major platform from the TRS-80 and Amiga, to today's high end, multi-core servers. Over the years, he has worked in many fields related to technology and computing, including system design, assembly and sales, professional quality assurance testing, and technical writing. In addition to being the Managing Editor here at HotHardware for close to 15 years, Marco is also a freelance writer whose work has been published in a number of PC and technology related print publications and he is a regular fixture on HotHardware’s own Two and a Half Geeks webcast. - Contact: marco(at)hothardware(dot)com