AMD, Nvidia graphics chip designs diverge

UPDATE: On Monday, Advanced Micro Devices and Nvidia are launching graphics chips based on distinctly different design philosophies.

Nvidia's GTX 280 and GTX 260 are designed to deliver the biggest performance bang per chip. A so-called "monolithic" approach packs 1.4 billion transistors and 240 processing cores onto one piece of silicon.

(See Peter Glaskowsky's review of the GTX 280.)

AMD's modular approach tends toward less is more: smaller, less power-hungry chips that can be strung together to achieve higher performance. The company plans to implement this strategy with the HD 4850 and HD 4870 graphics processing units (GPUs) that are being introduced on Monday. (See "Notes" below.)

This design philosophy is based on the same multicore strategy now employed by AMD (and Intel) for the CPU, the main PC processor. Instead of making one chip bigger and faster, AMD boosts performance by stringing together multiple chips. This approach also allows a chipmaker to avoid the time and expense of designing separate processors for the midrange and very-high-end segments.

(Clarification: In the case of a CPU, a core refers to a "scalar" x86 processor core found, for example, in a quad-core Intel or AMD chip. The GPU core is a "parallel processing core." GPUs these days typically contain hundreds of these cores.)

"The beauty of this design is that it's scalable. You can put one or two (chips) on a board," said Matt Skynner, vice president of marketing at AMD's Graphics Products Group.

In the midrange segment ($200 to $300) AMD uses a single chip--for example, an HD 4870. At the high-end ($500 and above), it adds another chip to scale up to better performance. This dual-chip design--code-named the R700--will be marketed as the 4870 X2.

On the other hand, Nvidia says its emphasis on a single, very-high-performance chip is necessary to keep it out front. "At the high end, there is no prize for second place," Ujesh Desai, general manager for GeForce products at Nvidia, said in an interview with Nanotech: The Circuits Blog last month.

(Nvidia also offers multichip designs, but it puts each chip on a separate board, while AMD puts two chips on one board.)

And Nvidia is trying to raise the bar with GTX 280. "We're rendering about 3 million triangles per frame," Curtis Beason, an engineer at Nvidia, said last month at an event where Nvidia previewed the GTX 280 chip.

"With (the previous-generation) GeForce 8800, what we achieved is a very photorealistic character. Very detailed skin. But it was a single character," Jason Paul, the GeForce product manager, said at the Nvidia event last month. "With GTX 200 what we're moving to is multiple highly realistic characters."

Nvidia is also boasting that a dual-core GTX 280 can convert a high-definition movie into iPod video format in 35 minutes, compared to about five hours for a quad-core CPU system with low-end integrated graphics.

Hewlett-Packard's Voodoo unit will be one of the first to adopt the new Nvidia GPUs. "We are excited to be one of the first companies in the world to offer the technology in the new Exhilaration Edition of the...HP Blackbird 002," said Rahul Sood, chief technology officer, HP Voodoo Business Unit.

Notes: updated 6/16, 12:10 PM:

--AMD 4800 series processors will be available starting next week at Besy Buy, according to AMD VP Rick Bergman, speaking Monday at an AMD event. "In just a little over a week from today. You'll be able to walk into a Best Buy and buy this chip (4800 series) on a graphics board for about $200. A teraflop for $200," Bergman said. He added that systems will also be available from Falcon Northwest, Velocity Micro, and ibuypower. "We're also introducing a system that can take four of these boards," he said. "That's almost five teraflops of performance in a personal computer."

--Both AMD and Nvidia say their GPUs can achieve about one teraflops (trillion floating point operations per second) of performance.

--Nvidia's GeForce GTX 280 will retail for $649 and be available on graphics boards starting Tuesday. The GeForce GTX 260 will be priced at $399, with availability slated for June 26.