In the realm of memory chips for graphic cards used in PCs and laptop computers, GDDR5 is becoming the next predominant DRAM standard, offering much higher memory bandwidths compared to other technologies, believes Robert Feurle, Qimonda Vice President Specialty DRAM. For this reasons, Qimonda early announced to skip GDDR4 and bet on GDDR5 instead. Now the company is about to ramp up the technology. According to Feurle, it is not only the end user who benefits from the technology but also computer manufacturers.

While the higher memory bandwidth drives the performance in discrete graphics systems higher by up to 40 percent, something the user can see on his computer, computer manufacturers benefit from high signal integrity and low power consumption. "GDDR5 lowers manufacturing costs since it is possible to use simple 4-layer boards for memory subsystems", explained Feurle. Typically, graphics memory PCBs currently require six layers.

In addition, the chips consume 30 percent less power than their GDDR3 counterparts. This redundantizes separate voltage control circuits required for graphic memories, explains Feurle. With mass production for buried-wordline chips scheduled for coming autumn, Qimonda developers will be able to reduce the I/O supply voltage to 1.2V and then to 1V which again will reduce power consumption. "We believe that in the future, the innovation in memory chip development increasingly will focus on power aspects," Feurle said in an interview with EE Times Europe. In order to reduce the power consumption, chip designers will optimize I/O circuits, do away with external power regulator ICs and, as mentioned, switch to buried wordline technology.

Having started the GDDR5 chip production in late 2007, the company believes the transition to GDDR5 in the mainstream market will take place in 2009. However, for early adopters and high-end users, the changeover has already begun, says Feurle.

At the same time, the company is already heading for higher densities. Currently, Qimonda manufactures standard GDDR5 512 Mbit devices as well as 1 Gbit memory chips. While in the GDDR3 market, the 1 Gbit devices already have surpassed 512 Mbit in terms of volume, this process will happen in the GDDR5 market in about three months, Feurle said. The company has implemented an aggressive roadmap to higher densities. 2 GBit devices are scheduled for ramp-up in 2010, and 4 GBit devices are already in sight, with the company's buried wordline technology being an important productivity booster since it enables smaller memory cells, Feurle said.

The development does not only aim at higher densities and lower power but to higher bandwidths as well. While the company presently has devices for data speeds of 4.0 Gbps and 5.0 Gbps in mass production, it is already working on faster chips. Qimonda engineers have built a 6.4 Gbps reference platform which will be available in the next chip generation. Unlike GDDR4 which will remain a technology for a small niche, GDDR5 is here to stay for a while, Feurle believes. "It has enough headroom for the about five years as the dominating standard," he said.