It seemed the general consensus after E3 last month was that Sony's PlayStation 3 would be slightly more powerful than the Xbox 360, but ATI says its GPU (Xenos) will have the advantage over rival Nvidia's RSX chip. The key, claims ATI, is that RSX doesn't have the unified shader architecture that Xenos does.
The long-standing battle between graphics cards manufacturers ATI Technologies and Nvidia Corp. has spilled over into the realm of the consoles. With Nvidia recently leaving Microsoft to join market leader Sony and ATI now providing the respective GPUs for two of the three next-gen systems, both companies will no doubt fiercely defend the platform their technology will be powering.
According to recent comments by ATI, despite the impressive visuals demonstrated by Sony during its pre-E3 press conference, Microsoft's Xbox 360 will be able to outperform the PlayStation 3 in the graphics department. Speaking with British hardware review and PC modification website bit-tech.net, ATI's Richard Huddy, who handles developer relations and worked at rival Nvidia for 4 years prior to ATI, said he believes the Xbox 360's architecture will enable Microsoft's next-gen system to match if not surpass the PS3's visual output.
"It's way better than I would have expected at this point in the history of 3D graphics," said Huddy of the Xbox 360 hardware. "The unified shader architecture alone is capable of giving a performance increase of a factor of nearly two over the hardware that we have in PCs today. That's because we see many cases, and this is particularly true on consoles, where games are limited by one of the two groups of engines in the graphics chip, either the vertex engines or the pixel engines. With a unified pipeline we can now devote 100% of the hardware to which ever task is the bottleneck."
Looking specifically at the difference between ATI's Xenos chipset for the 360 and Nvidia's highly touted RSX for the PS3, on paper the advantage would clearly go to RSX. But as the sub .500 New York Yankees are proving this baseball season, "on paper" doesn't mean a whole lot.
At 550MHz the clock speed of the RSX is 10 percent faster than the Xenos core, but Huddy claims that ATI's unified shader architecture is the key. "That mere 10% clock speed that RSX has on Xenos is easily countered by the unified shader architecture that we've implemented," he said.
ATI says that this unified architecture allows for 48 billion shader operations per second—a shader essentially is a program to alter the lighting, color, surface or other properties of each pixel.
"Rather than separate pixel and vertex pipelines, we've created a single unified pipeline that can do both. Providing developers throw instructions at our architecture in the right way, Xenos can run at 100% efficiency all the time, rather than having some pipeline instructions waiting for others," continued Huddy. "For comparison, most high-end PC chips run at 50-60% typical efficiency. The super cool point is that 'in the right way' just means 'give us plenty of work to do'. The hardware manages itself."
Nvidia, however, has pooh-poohed unified shader architecture, saying that it's not the best way to advance graphics technology. Huddy, though, is not surprised by Nvidia's stance. "This time around, they don't have the architecture and we do, so they have to knock it and say it isn't worthwhile," he said. "But in the future, they'll market themselves out of this corner, claiming that they've cracked how to do it best. But RSX isn't unified, and this is why I think PS3 will almost certainly be slower and less powerful."
It should be very interesting to see games created for both systems. Stay tuned.
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Subject: 360 has a better graphic capability then ps3? I thought it was the other way around :S 
