July 1, 2010 -- DDR3 DRAM is picking up steam in consumer and corporate markets, on the threshold of becoming the most widely available main memory accounting for over 50% of the DRAM on the market, beginning in Q1 2010.

The rapidly growing market for this high-performance memory is driven by the continuous growth of dual- and multi-core CPUs, multi-tasking operations, 64-bit operating systems such as Windows 7 and compute-intensive applications such as virtualization, 3D, gaming and photo/video editing. DDR3 operates at speeds up to 1600Mbps, providing double the bandwidth of its predecessor, and perhaps most importantly is available at voltages of 1.5V and green 1.35V – critical for sensitivity to excess power consumption, particularly important in data centers.

Figure 1. Newly introduced 4-Gbit, 40-nm Green DDR3 memory (for use in modules up to 32GBytes) will provide even more substantive power efficiencies than densities of 1Gbit and 2Gbit.

Beyond voltage, optimizing process geometry provides absolute power savings at the component and system levels. DDR3 is the first DRAM being produced using 40-nm process technology.

When production geometry and voltage are both considered, the combined savings in power consumption of 1.35-V 40-nm class 2-Gbit DDR3 can be as high as 73% over 1.8-V, 60-nm class 1-Gbit DDR2.

Figure 2. Industry DDR3 power reduction crossover projection for Q1 ’10 Source: Samsung Semiconductor.

Aligning with IT needs

The challenge and the opportunity for the server industry will be to align with the roadmaps of the major server CPU and memory providers. To do this, chip makers need to develop effective chip designs that ensure the scalability of server architecture, and augment the need for greater bandwidth and speed, in addition to reducing overall power consumption.

Green DDR3 fits this bill, nicely. From a global energy standpoint, its role in server system design can even be regarded as "critical." With already-high energy demands expected to rise considerably, IT budgets have been placed under heavier scrutiny. Moreover, a number of operational constraints and government regulations are cropping up, making this advanced memory selection all the more important.

Green data centers represent not only a vital step towards substantial energy savings around the globe, but also offer the opportunity for a substantial reduction in CO₂ emissions. Data centers are considered one of the worst contributors to air pollution along with the airline and coal industries because of their increasing rate of emissions. Therefore, optimizing data center server designs for energy efficiency will have an immediate, demonstrable impact. It is estimated that replacing the 11.5 million servers in the United States with DDR3-based servers using advanced 40-nm DDR3 memory, can save over 29 trillion watt-hours (Whr) of power per year (two billion dollars worth).

The power dilemma

Without optimization, the future energy picture in data centers becomes even bleaker. According to the EPA (U.S. Environmental Protection Agency), if no optimization occurs in the server space, the power consumption of servers – currently in the 100’s of billions of kilowatts – is expected to double in the years to come. When limited energy resources worldwide are considered in conjunction with economic growth in emerging sectors and expansion of Internet-related server traffic, energy saving is becoming not only a matter of corporate responsibility, but also a governmental priority.

For any given server, the degree to which memory contributes to overall power consumption is higher than most would think. Moreover, future increases in memory density will result in substantial increases in overall power consumption. In a 48-GByte FBDIMM DDR2-based server, for example, the contribution to total power consumption today is about 26%*.

Anyway we look at it, the environmental benefits of Green DDR3 are numerous. From a power/ performance perspective, when considering two comparable configurations with the same system workloads, a 40-nm, 2-Gbit based, 1.35-V DDR3 RDIMM consumes 1/5 the power* of DDR2 while providing twice the bandwidth. In fact, a server using Samsung’s 40-nm 1.35-V DDR3 saves 17% to 20% of system power even compared to a comparable 1.5-V DDR3 configuration.

As DDR3 sales continue to pick up, 40-nm process technology – together with a 6F² DRAM cell and adaptive design technology for smaller-sized chips – will play a key role in assuring supply levels at price points that facilitate broad IT acceptance.

Consequently, a total power/ performance efficiency improvement of 80% for Green DDR3 can be achieved compared to a server having a 1-Gbit, 60-nm, FBDIMM 1.8-V DDR2 configuration. These power efficiency improvements are essential for the new generation of servers. Actual measurements show that switching to 40-nm class DDR3 provides an additional 38% power savings* over a 60-nm equivalent DDR3 memory.

The clearest path to greater power savings, however, comes from using higher density memory components in addition to embracing lower voltages and finer process geometries. For a given memory configuration, Samsung’s 2-Gbit DDR3 memory, for example, saves 17% more power* compared to a 1-Gbit-based configuration. Moreover, building a module using 2-Gbit chips cuts down the number of components by 50% when compared to an equivalent 1-Gbit version. So, not only do we save on power efficiency, but we also reduce the total amount of raw material used.

Cumulative efficiencies

Our measurements also show that 40-nm, 2-Gbit, 1.35-V DDR3 achieves a remarkable 38% power savings at the system level. Larger densities will bring even greater improvements.

When considering a large server farm, the cumulative savings from memory optimization go even higher. They exceed that of individual servers since cooling infrastructure and equivalent associated maintenance costs also are sharply reduced.

Looking back, the 38% power reduction at the system level using 40-nm DDR3 solution equates to a 2,564kWhr per system saving per year. In three years, that amounts to an energy savings of up to 92TWhr, which for a 1200-unit server farm could save an estimated $6376M – enough money to purchase 1,821K more servers.

Considering that there will be 32 million servers worldwide by 2010, replacing them with new DDR3-based servers populated with 40-nm, 2-Gbit, 1.35-V memory has the potential of saving 82 trillion Whr of power or roughly $28 billion per year.

These savings equate to eliminating gas emissions from more than five million cars or cutting out construction of seven coal-based power plants, or preventing more than 34 million tons of CO₂ emissions from being released into the atmosphere every year.

Due to its high volume shipments and supply-and-demand dynamics, memory has often been portrayed as a "commodity." Green DDR3 takes DRAM out of the commodity realm. There is no doubt that IT managers are rapidly beginning to see 40-nm 1.35-V DDR3 as an essential part of a system design that finds a real silver lining in green advancements, from the twin perspectives of environmental sensitivity and total cost of ownership.

By Sylvie Kadivar.

Sylvie Kadivar is Director, Strategic DRAM Marketing, Samsung Semiconductor, Inc. * Based on Samsung Laboratories data using Samsung 40-nm, 2-Git, 1.35-V DDR3.