Unquestionably, the need for a green technology ecosystem is real, and 40nm 1.35V DDR3, the most advanced server memory technology today, is leading the way. In this contributed article, Sylvie Kadivar will examine the key benefits and metrics of Samsungs Green DDR3 technology and highlight the "green" efficiencies achieved when optimally combining process geometry, low voltage, high density and packaging.

DDR3 DRAM is picking up steam in consumer and corporate sales, on the threshold of becoming the most widely available main memory accounting for over 50 percent of the DRAM on the market, beginning in Q1' 2010.

Industry DDR3 Crossover Projection for Q1 '10 (Source: Samsung Elec. 12 '09)

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, thus providing double the bandwidth of its predecessor, and perhaps most importantly is available at voltages of 1.5 and green 1.35V " critical for sensitivity to excess power consumption, particularly important in data centers.

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

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

Click on image to enlarge.

Aligning with IT needs

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 40nm DDR3 memory, can save over 29 trillion watt-hours 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.

World leaders recently met in Copenhagen to discuss their nations' commitments in reducing CO2 emissions. And a month prior to that, the state of California passed far-reaching legislation mandating the production of more energy-efficient televisions to comply with Energy Star regulations. Recently, the EPA announced Energy Star specification guidelines for servers that will have considerable impact on the IT industry.

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 48GB FBDIMM DDR2-based server, for example, the contribution to total power consumption today is about 26 percent*.

40nm process technology

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 40nm, 2Gb based, 1.35V DDR3 RDIMM consumes 1/5 the power* of DDR2 while providing twice the bandwidth. In fact, a server using Samsung's 40nm 1.35Volt DDR3 saves 17 percent to 20 percent of system power even compared to a comparable 1.5V DDR3 configuration.

As DDR3 sales continue to pick up, 40nm process technology " together with a 6F 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.

Substantial energy savings

Consequently, a total power/performance efficiency improvement of 80 percent for Green DDR3 can be achieved compared to a server having a 1Gb, 60nm, FBDIMM 1.8V DDR2 configuration. These power efficiency improvements are essential for the new generation of servers. Actual measurements show that switching to 40nm class DDR3 provides an additional 38 percent power savings* over a 60nm 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 2Gb DDR3 memory saves 18 percent more power* compared to a 1Gb-based configuration. Moreover, building a module using 2Gb chips cuts down the number of components by 50 percent when compared to an equivalent 1Gb version. So, not only do we save on power efficiency, but we also reduce the total amount of raw material used. Green DDR3 now is available in densities of 1Gb and 2Gb, to insert into modules offering capacities from 1GB to 16GB or higher (example: 32GB module was developed using 50nm class 4Gb DDR3 in January 2009)

Cumulative efficiencies

Our measurements also show that 40nm 2Gb 1.35V DDR3 achieves a remarkable 38 percent power savings at the system level. Larger densities will bring even greater improvements (see www.samsung/DDR3 to calculate your own savings).

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 percent power reduction at the system level using 40nm DDR3 solution equates to a 2,564kWhs (kilowatt hours per system) saving per year. In three years, that amounts to an energy savings of up to 92TWhs, which for a 1200-unit server farm could save an estimated $6376M " enough money to purchase 1,821K more servers.

The potential is enormous

Considering that there will be 32Mu servers worldwide by 2010, replacing them with new DDR3-based servers populated with 40nm, 2Gb, 1.35V memory has the potential of saving 82 trillion watts/hour of power or roughly 28 billion dollars 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 40nm 1.35V 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.