AMD Commits to GDDR-5 Memory Roadmap

The company did not lay out any specific product plans, but executives said that in general, GDDR-5 is expected to be used for graphics

The company did not lay out any specific product plans, but executives said that in general, GDDR-5 is expected to be used for graphics memory, while DDR-3 will be used for mainstream PC memories. Both will ramp during 2008 and enter mainstream volume production in early 2009, according to AMD's projections. In AMD's server roadmap, however, DDR-3 support won't be included within an AMD processor until 2010.

"Today's there's not a one-size-fits-all DRAM," said Joe Macri, senior director of graphics engineering at AMD, in an interview.

For AMD, however, GDDR-5 fills more of that role. Macri said the design of GDDR-5 allows for both aggressive power management as well as high-speed communications. GDDR-5, which is a single-ended architecture, is backwards-compatible to earlier DDR memories. Essentially, the higher data rates supported by GDDR5 – up to 5x that of GDDR3 and 4x that of GDDR4 – enable more bandwidth over a narrower memory interface, which can translate into superior performance delivered from smaller, more cost-effective chips, AMD said.

According to Macri, GDDR-5 could run in three modes: from 2.5 to 5.0 Gbits/s, from 1.0 to 3.0 Mbits/s, and from 200-Mbits/s to 1.5 Gbits/s. The latter would be considered a low-power mode.

Cost-wise, GDDR-5 memory commands about a 20 percent premium over GDDR-4 memory, Macri said.

The GDDR-5 spec has yet to be ratified, said Macri, who also serves as the chairman of the JEDEC DRAM standards group. Macri said he expects that standard to be ratified in September. However, that hasn't stopped companies like Qimonda from shipping early versions. Qimonda has already started mass production and the volume shipping of GDDR5 512Mbit components with a speed of 4.0 Gbits/s to AMD, the company said Wednesday.