[Pc_Support] Re: Reducing Electricity Costs -- bulbs first and foremost ...

[Bryan J. Smith]

Derek Konigsberg <octo at logicprobe.org> wrote:
> Frankly, I find these numbers quite interesting.  It goes to show
> that an  Athon64 whizbanger uses a lot less power than you'd
expect,

Why would you assume otherwise?

Even though AMD lags Intel 12+ months in multi-billion dollar
fabrication technology out of lack of fund reserves, their 1999
design is much more efficient than the NetBurst hack.

Simple rule of series and scalability:  

- Intel i686 (PPro-PIII-PM) scales from 200-1.0GHz, 1.5GHz with first
async refit, 2.1GHz with redesign (Pentium M).  7+1 pipelines (2 ALU,
2 FPU + 1 SSE in P3) with stages are typically 12 or less.

- AMD K7-8 scales from 500MHz to 2.0GHz, 2.8+GHz with refits.  9
pipelines (3 ALU, 3 FPU) with stages typically 20 or less.

- Intel NetBurst (P4) scales from 1.5GHz to 3.5GHz, 4.0+GHz with
refits.  7+2 pipelines (2 ALU, 1+1 FPU + 2 SSE) with stages typically
40 or so.

Intel i686 is more power efficient MHz for MHz than AMD K7-8, but the
latter scales higher.  The Intel NetBurst has a much higher MHz
scalability, but absolutely sucks up both power and wastes stages.

The concept that AMD uses more power than Intel _died_ once the
NetBurst hack was introduced.  Intel is _dropping_ NetBurst and going
back to i686 for new products.  They are clearly giving up the MHz
crown (they've already lost the performance crown) for power
efficiency.

The current 2.1GHz Pentium-M products use as little as 21W, no more
than around 45W at full load.

The AMD Athlon 64 1.8-2.4GHz (3000-3700+) use as little as 31W, no
more than 55W at full load.

Intel NetBurst can't break less than 70W.  Then again, NetBurst was
designed rather quickly, and did not have a full development cycle --
unlike i686 or K7-8.


-- 
Bryan J. Smith     Professional, Technical Annoyance
b.j.smith at ieee.org      http://thebs413.blogspot.com
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*** Speed doesn't kill, difference in speed does ***