SAN JOSE, Calif. Three DRAM makers are shipping parts using a new interface initially supporting data transfers at 4 Gbits/second per pin. The chips will serve a new generation of graphics controllers expected from Advanced Micro Devices and archrival Nvidia as early as June.
Hynix, Qimonda and Samsung are now shipping chips using the GDDR5 interface defined by Jedec. The spec, which could be officially published in September, adds new features to lower power and cost while increasing bandwidth over today's mainstream GDDR3 interface.
Joe Macri, senior director of circuit engineering for AMD's graphics group, said he expects AMD, Nvidia and Intel to use the interface on their next-generation graphics controllers. The interface will also be a good choice for next-generation videogame consoles, said Macri, who chairs both the DRAM committee at Jedec as well as the task group that defined GDDR5.
"We would not have three vendors bringing DRAM products to market in such a short space of time if only one vendor was going to support it," said Macri. "Intel, Nvidia and others were all there defining [GDDR5], and I suspect will design with it."
Alignment in the last generation spec was less strong. AMD supported GDDR4 for some of its high-end cards, but Nvidia stayed with GDDR3, extending bus width on its controller to 512 bits to improve performance.
Macri said Nvidia helped define GDDR4 but decided not to use it because it used 8 bits minimum for certain burst operations. Nvidia's graphics chip at the time was designed for a more traditional four-bit burst.
With just one graphics vendor using the spec, only two DRAM makers chose to support GDDR4.
"The ecosystem never fully developed," said Macri. "It achieved its technical goals, but it never did as well in the market as it could have."
Just what the next-generation controllers will offer and when they ship is still unclear. Thus it's also unclear whether AMD and Nvidia will use GDDR5 on all their next-gen chips or only for the highest end parts.
Intel has announced it is working on a discrete graphics controller it calls Larrabee based on an array of modified x86 cores. Intel said it will not release the part until sometime in 2009 and won't give any design details of it. However, Intel is expected to demonstrate a working prototype of Larrabee at Siggraph in August.