DEC veterans prepare chip challenge for Intel, AMD, IBM and S un

Robert M. Riches Jr. rm.riches at verizon.net
Wed Oct 26 00:43:46 UTC 2005


> Date: Tue, 25 Oct 2005 12:41:42 -0700 (PDT)
> From: "Bryan J. Smith" <b.j.smith at ieee.org>
>
> "Hoover, Tony" <hoover at sal.ksu.edu> wrote:
> > I wonder if this will change Apple's decision to abandon
> > the Power on future generations of Mac? 
>
> Why would it?
>
> #1  It is clearly "Power" and _not_ "PowerPC."  There is far
> more difference in the silicon beside just Altivec.  MacOS/X
> runs on PowerPC, _not_ Power.
>
> #2  It is clearly geared towarded embedded and low-power, not
> performance desktops.  AMD and Intel are still pushing out
> processors that eat 25-50W.  These suckers are 5-13W, clearly
> more towards high-power embedded, but far too low for
> desktop/server.
>
> Lastly, I don't really think the Register is a reliable
> source for many things.  I.e., they refer to this company as
> an "IT company" when they are a semiconductor start-up (even
> if fabless).

I can't speak for any difference between the Power and
PowerPC instruction sets, but I can offer a perspective on
chip power consumption vs. performance.

The PA Semi story was all over the financial headlines for
related stocks symbols yesterday (Oct. 24).  While the chip
is supposed to be much lower power than conventional chips,
it is supposed to have very good performance.  For a given
FAB process and such, if you graph performance as a function
of power consumption, the curve is strongly concave up.  On
the end denoting high power and high performance, the curve
is extremely steep, nowhere near linear from the lower part
of the curve.  Put another way, the last 90% of power
consumption may only give 20% extra performance.  A good
macro-architecture, a good micro-architecture, and a
brilliant design team can gain back most of that 20%
performance while keeping most of the 90% power reduction.

Yahoo has a story that says the processor will have two
2-GHz cores.  That ought to be fairly respectable.  I
wouldn't be surprised to see a chip with acceptable
performance for at least desktop use, definitely acceptable
for laptops, and maybe good enough for some servers.  For
servers, don't forget that supplying power to and removing
heat from a few dozen high-density server racks packed into
a small machine room can cost a lot of money.  If you can
get 80% of normal performance and only use 40% of normal
power, you can use 25% more servers and save a lot of money
in power and cooling.  (I heard of a special deal in which a
large search engine company bought a huge number of special
reduced-power processors from a large semiconductor maker,
and power reduction was the primary goal.)

(For credibility evaluation, my previous job was overseeing
the technical side of schematic formal verification of the
Pentium 4 processor.  I had been on the design teams of
three other processors before that.)

Robert Riches
rm.riches at verizon.net
rmriches at ieee.org




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