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Power Hardware Technology

Advance In PCM Memory Could Dramatically Reduce Power Consumption 74

Zothecula writes "Researchers from the Electrical and Computer Engineering Department of the University of Illinois have developed new low-power digital memory which uses much less power and is faster than other solutions currently available. The breakthrough could give future consumer devices like smartphones and laptops a much longer battery life, but might also benefit equipment used in telecommunications, science or by the military."
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Advance In PCM Memory Could Dramatically Reduce Power Consumption

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  • Sheesh... (Score:2, Informative)

    by ibsteve2u ( 1184603 ) on Tuesday March 15, 2011 @12:44AM (#35488008)
    Five moderator points, and no comments worth reading.
  • by Anonymous Coward on Tuesday March 15, 2011 @12:55AM (#35488056)


    Phase-change materials (PCMs) are promising candidates for nonvolatile data storage and reconfigurable electronics, but high programming currents have presented a challenge to realize low power operation. We controlled PCM bits with single-wall and small-diameter multi-wall carbon nanotubes. This configuration achieves programming currents as low as 0.5 A (SET) and 5 A (RESET), two orders of magnitude lower than state-of-the-art devices. Pulsed measurements enable memory switching with very low energy consumption. Analysis of over 100 devices finds that the programming voltage and energy are highly scalable, and could be below 1 V and single femtojoules per bit, respectively.

  • How do clear bits? (Score:4, Informative)

    by Michael Woodhams ( 112247 ) on Tuesday March 15, 2011 @01:33AM (#35488194) Journal

    TFA explains how to set a bit (from 0 to 1), but not how to clear the bit.

    The actual paper in inaccessible to me (without $$$), even from a university, as it is pre-publication. (I think it will become available on the 17th.)

  • by Anonymous Coward on Tuesday March 15, 2011 @01:58AM (#35488278)

    uses much less power and is faster than other solutions currently available

    Haven't seen however any info on the speed.

    Unless I'm reading it wrong -- and the wording is a bit ambiguous -- they seem to be claiming speeds higher than other PCM implementations, not DRAM. I would be very surprised if the write speed of phase-change memory could ever exceed that of DRAM, and I say write speed because phase-change devices can be read faster than they can be written.

    PCM is much more likely to be a SSD solution than a replacement for main memory, and even then, it's a long, long way from leaving the lab. All this announcement concerns is a proof-of-concept.

  • by TheRaven64 ( 641858 ) on Tuesday March 15, 2011 @06:18AM (#35489256) Journal
    Actually, the headline reads 'Advances in Phase-Change Material Memory...' if you want to expand the initialism. PCRAM is the more common abbreviation for phase change (random access) memory. It's a very interesting technology for persistent storage, for two reasons. The first is that, like DRAM, it's byte-addressable. The second is that read speeds are almost as fast as DRAM. This means that you can just map a bit of it into a process's address space, without any copying, to make the data available. It's a good contender for swap / hibernate space, because you can write pages that haven't been modified recently out to PCRAM, update the page tables to point there, and then turn off DRAM chips. Writing to PCRAM is quite a bit slower than writing to DRAM, but is probably fast enough when you're in power-saving mode, so you can turn off all of the DRAM, and only turn it on when the system load increases again.

Who goeth a-borrowing goeth a-sorrowing. -- Thomas Tusser