SAN FRANCISCO Sony Computer Entertainment Inc. has disclosed more details of its latest graphics rendering engine, a 462-mm2 beast that makes the company's Graphics Synthesizer chip featured in Sony's Playstation 2 look like child's play.
The device contains 256-Mbit of on-chip embedded DRAM, or eight times more than the current Graphics Synthesizer. The DRAM and wide 2,000-bit internal buses can deliver 48 gigabytes per second of bandwidth.
In raw graphics performance, the chip can process 75 million polygons per second, has a pixel fill rate between 1.2 and 2.6 gigapixels/s and can draw 75 million polygons/s, according to Aurangzeb Khan, vice president of Simplex Solution Inc. (Sunnyvale, Calif.), who presented a paper on the graphics processor here at International Solid-State Circuits Conference.
Simplex worked with Sony Computer Entertainment and other Sony divisions to come up with the physical design of the chip using its hierarchical design methodology. Simplex plans to commercialize the EDA tool, which can generate "black box" timing models, by June, Khan said.
Using 0.18-micron design rules, the latest Graphics Synthesizer is an astounding 21.7 x 21.3-square-millimeters and contains 287.5 million transistors, with embedded DRAM taking up most of the silicon real estate. By contrast, the current Graphics Synthesizer in the Playstation 2 uses 42.7 million transistors and measured 16.8 x 16.8 mm when it was first introduced on a 0.25-micron process.
Khan said the latest incarnation of the Graphics Synthesizer is as big as a chip can get from a manufacturing point of view. "It barely fits on the reticle," he said.
The device contains so much on-chip memory that it turns the embedded DRAM adoption model upside down. Normally, standalone DRAMs are the highest-density memories on the market, while devices that combine logic and embedded memory sport only a fraction of that memory density. Most DRAM makers aren't planning to move to 256-Mbit standalone DRAMs until they shift to new 0.15- or 0.13-micron process technologies.
Yield is one obvious concern with a chip this size, though Khan said Sony is satisfied with current yields at this point. He would not say whether the chip would be used in a follow-up version of the Playstation 2.
Sony has taken gambles before with chip size. It's 128-bit MIPS-based Emotion Engine processor, first manufactured on a 0.25-micron process, was considered too large to be used profitably in the Playstation 2, given Sony's price for the console. Game console makers traditionally subsidize the high cost of their hardware through sales of game titles, especially in the early stages of manufacturing. Sony, however, hit some snags in the manufacture of its Graphics Synthesizer for the Playstation 2 last year, which hindered the number of consoles it could sell.
The latest graphics chip was demonstrated last year at Siggraph 2000 in New Orleans.
Sony's 128-bit Emotion Engine CPU may soon find a place outside the Playstation. Toshiba America Electronic Components Inc. (San Jose, Calif.) has been working to develop a core version of the processor, which it expects to introduce to market in several months. It's parent company, Toshiba Corp., manufactures the Emotion Engine for Sony.
Toshiba has expressed interest in offering the 128-bit processor for high-end routers and switches. The core will be one of the first processors to undergo significant rework and tuning by Toshiba's U.S. subsidiary, said James Smith, director of business development for Toshiba's MPU division.
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