Hence, the same 48 GB server configured with third generation Green DDR3 DRAM chips will reduce the memory power consumption dramatically. Measured data shows that by replacing second generation 60 nm 1 Gb DDR2 DRAMs operating at 1.8 V with 30 nm 4 Gb DDR3 DRAM chips operating at 1.35 V, the total power consumed by DRAM memories in each server is reduced from 102 W to 14 W, reaping a whopping 86% savings. This means that at the component level, the Green DDR3 can deliver technology that can consume less than 0.29W per Gigabit of memory as opposed to 2W per Gigabit.
However, to better gauge this at the system level, let us compare the power scenario for a specific 42U server rack comprising four enclosures per rack with 16 servers in a single enclosure for a total of 64 servers or blades per rack. The above mentioned configuration equates to system-level power savings of about 44% -- from 390 watts to just 220 watts.
The 44% saving at the server level equates to significant TCO benefits in the enterprise space: Through the use of Green DDR3, buyers can increase server resources 80% without needing to increase the power budget. In a 2000W power envelope, Green DDR3 allows for placing nine servers on a single rack instead of five. The savings become even more significant when one factors operating costs. For example: In a 1,000-server farm, only 112 racks would be needed instead of 200, cutting overhead costs proportionately by more than $60,000.
Moving to a Green DDR3 provides yearly energy savings of 2.98 Megawatt hours of electrical power per year per server, which amounts to an annual dollar savings of $194,000 per 1,000 servers. That much money would allow the purchase of another 55 servers after just one year of use. Or, simply result in a power cut of 3,000 megawatt hours over the same period of time.
SSDs bring greater savings
Additionally, optimized server architectures are taking advantage of the benefits of solid state drives (SSDs). Exploiting NAND flash technologies, SSDs are aiding optimized servers to further curtail power use and cutting associated cooling costs. With digital design and no moving parts, SSDs save much more power than traditional hard disk drives (HDDs). In comparison to a conventional 15K rpm HDD, certain SSDs can use only 1.7W in active mode for a 79% drop in power consumption. Power savings in the idle mode is even greater -- about 83% compared to a 15K rpm HDD.
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