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Re: Green Array energy consumption: a reality check.

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On 2014-01-12, Albert van der Horst <albert@spenarnc.xs4all.nl> wrote:
> I've recently looked at the Green Array chips with bitcoins
> in mind. With the current state of affairs a bitcoin is
> approximately worth the expense in energy consumption to
> generate it. This looks like a promissing area for the GA144.

> There is special hardware to do 300 GigaHash/second at 175 Watts.
> Not even considering whether it is even possible to harness
> the GA144 to arrive at this level of bulk performance, lets
> look at the energy picture.

> With a device like that one hash is calculated at the tune of
> 600 pJ. This is all in, for a device that you can buy right now.
> (butterfly bitcoin miner).

From the Butterfly Labs FAQ <http://www.butterflylabs.com/faq/>:

| What is the power consumption of the Bitforce SC (ASIC based) units?
|
| Our 65nm chips consume between 4 and 5 watts per gigahash.
| ...
| Our 50 gigahash machine will consume approximately 250 to 300 watts.

5 watt-seconds per gigahash is 5 nJ/hash, 5000 pJ/hash.

> A SHA256 costs 64 rounds with about 16 operations, not counting
> the rotations (that promise to be very expensive on the GA144).

> If we are optimistic and
> - totally ignore communication overhead,
> - ignore cross wiring involved in the rotations,
> - assume that a 32 bit operation costs merely two GA144 cycles
> - assume the minimum energy Green arrays mentions for an operation (7pJ).

> we arrive at 2*1000 * 7 is 14,000 pJ.

> This looses out at a fat order of magnitude.

You're comparing the power consumption of a general purpose computer with
that of ASIC (application specific ic). Fixed rotations and shifts cost
_no_ energy in hardware, and there's no overhead. ASICs win at everything
except flexibility and small quantity cost...

Tristan

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Thread

Green Array energy consumption: a reality check. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-01-12 15:18 +0000
  Re: Green Array energy consumption: a reality check. Tristan Plumb <firth@trstn.net> - 2014-01-12 17:02 +0000
    Re: Green Array energy consumption: a reality check. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-01-12 17:27 +0000
      Re: Green Array energy consumption: a reality check. Tristan Plumb <firth@trstn.net> - 2014-01-12 22:40 +0000
        Re: Green Array energy consumption: a reality check. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-01-12 23:03 +0000
          Re: Green Array energy consumption: a reality check. Paul Rubin <no.email@nospam.invalid> - 2014-01-12 16:54 -0800
  Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-13 02:45 -0500
    Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-13 02:54 -0500
      Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-13 02:57 -0500
    Re: Green Array energy consumption: a reality check. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-01-13 12:32 +0000
      Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-13 09:52 -0500
        Re: Green Array energy consumption: a reality check. mszepien@gmail.com - 2014-01-19 11:01 -0800
          Re: Green Array energy consumption: a reality check. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-01-19 19:38 +0000
            Re: Green Array energy consumption: a reality check. mszepien@gmail.com - 2014-01-19 13:40 -0800
              Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-19 17:50 -0500
                Re: Green Array energy consumption: a reality check. mszepien@gmail.com - 2014-01-20 12:55 -0800
                Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-20 16:34 -0500
                Re: Green Array energy consumption: a reality check. mszepien@gmail.com - 2014-01-21 04:49 -0800
                Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-21 10:48 -0500
                Re: Green Array energy consumption: a reality check. mszepien@gmail.com - 2014-01-21 14:37 -0800
                Re: Green Array energy consumption: a reality check. albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-01-22 19:30 +0000
    Re: Green Array energy consumption: a reality check. "Rod Pemberton" <dont_use_email@xnohavenotit.cnm> - 2014-01-27 16:26 -0500

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