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Spansion, Virident aim to slash power in server farms

Spansion based a new device—EcoRAM—on its existing Eclipse chip architecture, which blends NOR and NAND to achieve both fast access and high-bandwidth update.

By Ron Wilson, Executive Editor -- EDN, 6/24/2008

NOR flash vendor Spansion Inc and server architecture start-up Virident Systems Inc teamed this morning to announce a new approach to slashing power consumption—and hence, total cost of ownership—in the massive server farms that lie at the foundation of the Web.

By creating a new category of flash memory with one-eighth the average operating power and eight-times the bit density of DRAM DIMMs, Spansion hopes to enable a sea change in the way server farm managers implement memory. And by making this new flash device transparent to the rest of the server hardware and software, Virident intends to make the switch-over from DRAM to flash painless and profitable for the managers.

The problem the two companies are attacking is power consumption in server memory. Jonathan Koomey, professor at Stanford University, began today’s presentation with some summary data on server energy consumption, indicating that in 2005, servers of various flavors were consuming about 1% of the world's electricity. He projected that by 2010, the consumption rate in kw would have doubled.

Bertrand Cambou, CEO of Spansion (pictured left), narrowed the focus to the energy consumed in DRAM in search-based Web-services farms. He pointed out that because of the necessity for fast search response, organizations like Google had to maintain huge, loosely structured data tables in DRAM rather than on disk. That meant keeping DRAM continuously active and refreshed with quasi-static data: search tables that might be updated only once an hour or once a day.

The ideal solution for this data, Cambou argued, was not DRAM, but a non-volatile memory that could provide read-access parity with DRAM, update in a reasonable time, but have a fraction of the power consumption. Conventional NAND flash would not work, Cambou observed, because of the abysmal random access speed. Conventional NOR would not work either, because of the low update speed.

So Spansion based a new device—EcoRAM—on its existing Eclipse chip architecture, which blends NOR and NAND to achieve both fast access and high-bandwidth update. Based on Spansion's Mirror-bit technology, EcoRAM (pictured right) is ready to ship in 2-Gbit, 65-nm parts, making possible a 32-GByte DIMM with the same speed, form factor, and power as a 2-GByte DRAM DIMM. The company's roadmap calls for them both to ship 4-Gbit, 45-nm parts and to tape out 8-Gbit, 32-nm parts in 2009.

Virident's role, as explained by president and CEO Raj Parekh, is to fit the Spansion EcoRAM DIMM seamlessly into existing server architectures. Without going into details on what is as yet an unannounced product, Parekh said Virident would provide a pair of chips, some additional hardware, and a considerable amount of software that would allow existing servers to run existing operating systems and applications, while benefiting from the huge increase in memory capacity (or huge drop in power) offered by the EcoRAM.