AMD sticking with DDR memory in 2005

HANOVER, GERMANY -- While the PC industry is expecting the transition to DDR2 (double data rate 2) memory to get under way later this year, Advanced Micro Devices (AMD) has no plans to modify its current chips to support DDR2 this year, the company said Friday at the Cebit trade show in Hanover, Germany.

DDR2 is expected to become the successor to DDR SDRAM (synchronous dynamic RAM), the current standard for PC memory. DDR2 chips can run at faster speeds than current DDR memory chips, but most of the PC industry is still using DDR memory chips.

PC makers have been reluctant to support DDR2 technology because of the added cost to their systems, despite the availability of processors and chipsets from Intel that have supported the technology since last June. However, those costs are expected to change this year.

In January, memory market share leader Samsung Electronics said that the majority of its memory chip production in the second half of 2005 will adhere to the DDR2 standard, and fellow memory manufacturers Micron Technology and Infineon Technologies are also planning increases in DDR2 production. When memory makers decide to increase production, prices fall as supply rises.

Despite the coming of those price cuts, DDR2 support still doesn't make sense for AMD in 2005, said John Crank, business development manager for the microprocessor business unit of AMD's Computation Products Group.

AMD's Athlon 64 and Opteron processors use an integrated memory controller, which produces impressive results on memory-intensive applications but requires that the chip be designed for a single memory standard. Intel's chips handle the complexity of the memory-processor interface in the chipset, which is easier and less expensive to tweak for new memory standards than having to redesign a processor.

With dual-core desktop and server processors expected this year, AMD could have chosen to build DDR2 support into this latest revision of its processors. But DDR2 memory support won't become necessary for AMD until DDR2 chips running at 667MHz cost as much as current DDR chips running at 400MHz, Crank said.

AMD's integrated memory controller design is much more sensitive to latency, or delays in a signal's journey from one point on a chip to another, Crank said. The first DDR2 chips run at 400MHz and 533MHz, and that's not fast enough to overcome the increased latency associated with DDR2 memory, Crank said. Internal tests of AMD systems with 400MHz and 533MHz DDR2 chips actually ran slower than systems with 400MHz DDR chips, he said.

By the time 667MHz DDR2 chips roll around, AMD will be ready to embrace the new standard, Crank said. This should take place at some point in 2006.