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First probabilistic CPU 30x more power-efficient

updated 04:25 pm EST, Sun February 8, 2009

Rice University PCMOS

Rice University today used the International Solid-State Circuits Conference to reveal that it has tested a real-world example of a processor founded on probability math. Called a PCMOS (probability-based complementary metal-oxide semiconductor), the chip abandons the either/or Boolean logic of all current processors in favor of calculations that rely on the most likely answer in most cases. By avoiding a reliance on getting an exact answer when unnecessary, the CPU uses just a fraction of the power to accomplish the same work as today's chips; the example chip's voltage is dropped to where it consumes 30 times less power than an equivalent, ordinary CMOS processor.

As it has to wait less often for answers, the result is also about seven times faster and is especially suited to math where imprecision is unnoticeable or even encouraged, such as small image rendering or data encryption. The Houston-based university believes PCMOS would be particularly useful for typical home users in cellphones, video cards and other devices with embedded processors.

Co-developed with Singapore's Nanyang Technological University, the technology is still in the early stages but, according to inventing professor Krishna Palem, should enter real-world production within the next four years.

By Electronista Staff
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  1. testudo

    Forum Regular

    Joined: Aug 2001



    because we all want computers that are 'kinda' correct.

  1. godrifle

    Fresh-Faced Recruit

    Joined: Jan 2006




  1. cal6n

    Junior Member

    Joined: Nov 2003


    Douglas Adams...

    ... would be rather pleased!

  1. csimon2

    Junior Member

    Joined: Aug 2000


    go ahead testudo...

    keep making comments on things that you obviously don't have the ability to comprehend the significance of.

  1. Nai no Kami

    Senior User

    Joined: Aug 2000


    This is huge

    we are one step closer to the incarnation of Skynet

  1. Guest

    Fresh-Faced Recruit

    Joined: Nov 1999



    But you need a cup of warm tea to operate it.

  1. Loren

    Fresh-Faced Recruit

    Joined: Mar 2001


    So we've had...

    CISC, then
    RISC, and now
    GISC!! Guesswork Instruction Set Computing!!

    I think I love it.

    Remember, traffic lights are only guidelines.

  1. Guest

    Fresh-Faced Recruit

    Joined: Nov 1999


    Encryption?! Really?

    Because it really shouldn't matter if your secret key is off by a few bits, right? Right. Didn't think so.

    To add a little context where due: The type of encryption where probabilistic logic may come in handy is not your run-of-the mill AES or RSA algorithm, but rather a technique called "hyper-encryption" in which truly random bits are generated at very high speeds and the message is encrypted using only a select few of those bits. There's better info on WIkipedia about this, but for now let's just say a really fast true random number generator would be much better suited for Hyper-encryption than probabilistic boolean logic which is correct most of the time.

    And in an algorithm like AES a single wrong bit will change about half of all output bits in EVERY round due to the avalanche property of that block-cipher. So, no, PCMOS is not suitable for AES.

  1. Jonathan-Tanya

    Fresh-Faced Recruit

    Joined: Oct 2004


    all wrong

    one correction, the chip is actually wrong most of the time, but you take the results, flip it, and do the opposite.

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