News

Faster NOR Flash to replace DRAM?

posted on 25 June 2008 13:45

Spansion hopes - but praying might be better

NOR flash supplier Spansion has invented a faster form of NOR flash and is intending it for DRAM replacement, citing its better energy efficiency.

Spansion says NAND flash has 1/800th the random read speed of DRAM. NOR Flash is better but still a lot slower. It has invented a new form of NOR flash using MirrorBit technology, and christened it EcoRAM saying it has:-

-- Read performance to meet the requirements for fast random access
-- 1/8 the energy consumption of DRAM
-- 10x the reliability compared to DRAM
-- Die densities two-to-four times greater than conventional floating gate NOR
-- Write performance two-to-ten times greater than that of traditional NOR Flash memory

Reading the performance words carefully we see 'Read performance to meet the requirements for fast random access.' We don't see read performance equivalent to DRAM or faster than DRAM, so it is most likely slower and quite possibly a lot slower. In a Frost & Sullivan white paper (downloadable below) it's suggested that a server's DRAM is replaced by a smaller amount of DRAM and a relatively large amount of EcoRAM.

A Spansion PowerPoint slide suggests that EcoRAM read speed is 20 - 90% of DRAM read speed, a fairly wide range. No detailed read speed numbers are given out.

According to Spansion, MirrorBit technology, which is a bit like multi-level cell technology in NAND flash, offers higher yields than traditional floating gate NOR, and scales more easily to higher densities. When compared with floating gate NOR technology, MirrorBit technology offers a simpler memory cell, which requires fewer critical manufacturing steps to produce than competing floating gate technologies. As a result, MirrorBit technology can be produced at a lower overall wafer cost.

Spansion claims that, when combined with Virident Systems, Inc.'s new GreenGateway technology announced today, Spansion EcoRAM can help slash energy consumption by up to 75 percent in Internet data center servers, and offer four times the memory capacity of traditional DRAM-only servers for the same energy consumption.

Rufus Connell, VP North American ICT (Information and Communication Technology) Research Practice for Frost & Sullivan, says: "There is a class of applications in data centers that are constrained by the addressable main memory a server can handle. Solutions such as Spansion's, revolving around creative use of technology are critical for solving the growing energy crisis in data centers. As memory-bounded apps such as search use grow, conventional server architectures are failing to keep up with the increasing number of queries per second from consumers, which means more servers are needed and more power is needed to run and cool them. It is a real problem for data center operators globally and a solution to help save energy and reduce total cost of ownership is needed sooner rather than later."

Well.... this is all very interesting but comes out of the blue and requires a server supplier to take a punt on the idea and see what the performance/energy tradeoff is like.

PS. Who is Virident?

The company describes itself thus: Virident is the creator of the first green data-centric technology platform that will deliver a new class of green memory, servers and applications for the data center. Virident's core technology platform delivers energy efficiency, improved server utilization, TCO, and service continuity to companies seeking to meet the demands of Internet-Scale. Virident's GreenGateway technology transforms today's compute-centric servers into large memory data-centric industry standard servers. Virident makes green and growth possible in the internet data center. Founded in 2006 by notable Silicon Valley veterans from Sun, SGI, Google and Intel, Virident is headquartered in Milpitas, California. For more information visit www.virident.com.

PPS. Read Spansion's EcoRAM press release here.